Hindawi Publishing CorporationInternational Journal of OceanographyVolume 2013 Article ID 501602 16 pageshttpdxdoiorg1011552013501602

Research ArticleComparative Analysis of Sea Surface Temperature Pattern inthe Eastern and Western Gulfs of Arabian Sea and the Red Sea inRecent Past Using Satellite Data

Neha Nandkeolyar1 Mini Raman2 G Sandhya Kiran1 and Ajai2

1 Department of Botany Faculty of Science MS University Baroda Vadodara 390002 India2Marine Optics Division Marine and Planetary Sciences Group Space Application Centre Ahmedabad 380015 India

Correspondence should be addressed to Neha Nandkeolyar nehanandkeolyargmailcom

Received 1 January 2013 Revised 15 March 2013 Accepted 7 May 2013

Academic Editor Swadhin Behera

Copyright copy 2013 Neha Nandkeolyar et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

With unprecedented rate of development in the countries surrounding the gulfs of the Arabian Sea there has been a rapid warmingof these gulfs In this regard using Advanced Very High Resolution Radiometer (AVHRR) data from 1985 to 2009 a climatologicalstudy of Sea Surface Temperature (SST) and its inter annual variability in the Persian Gulf (PG) Gulf of Oman (GO) Gulf of Aden(GA) Gulf of Kutch (KTCH) Gulf of Khambhat (KMBT) and Red Sea (RS) was carried out using the normalized SST anomalyindex KTCH KMBT and GA pursued the typical Arabian Sea basin bimodal SST pattern whereas PG GO and RS followedunimodal SST curve In the western gulfs and RS from 1985 to 1991-1992 cooling was observed followed by rapid warming phasefrom 1993 onwards whereas in the eastern gulfs the phase of sharp rise of SSTwas observed from 1995 onwards Strong influence ofthe El Nino and La Nina and the Indian Ocean Dipole on interannual variability of SST of gulfs was observed Annual and seasonalincrease of SST was lower in the eastern gulfs than the western gulfs RS showed the highest annual increase of normalized SSTanomaly (+064decade) followed by PG (+04decade)

1 Introduction

In todayrsquos era one of the greatest challenges faced by hu-mankind is ldquoglobal warmingrdquoThere has been a 06∘C increasein global temperature in the last century and it is projected tofurther increase by 18∘C to 4∘C in the 21st century [1] posinga serious threat to the socioeconomic sector worldwideWithoceans covering approximately 72 of the earthrsquos surface anydiscussion on climate change and global warming wouldremain incomplete without including the role of the oceansStudies have revealed that because of the increase in green-house gases the oceans are warming significantly which isaffecting the marine ecosystem [2ndash5] resulting in shifting ofhabitats and dwindling of marine biota Most of the studieswith respect to climate change have focussed on global scalechanges [5ndash15] However an exhaustive analysis at theregional and local levels is needed for framing adaptive andmitigative strategies to alleviate the effect of global warming

In the Indian context the recent finding that amongst theoceans the warming of the Indian Ocean is second highest[15] is a cause of worry and calls for immediate attentionEven though climatological studies have been done in the pastin the Indian Ocean encompassing the Arabian Sea and theBay of Bengal [16ndash20] a comparative analysis of the changingSea Surface Temperature (SST) pattern the gulfs of ArabianSea (Persian Gulf Gulf of Oman Gulf of Aden Gulf ofKutch and Gulf of Khambhat) and the Red sea has not beendone The gulfs of the Arabian Sea are not just strategicallyimportant with rich sources of oil and natural gas but are alsothe hot spots of the marine biodiversity [21ndash28] However inthe recent years there has been an expeditious change in themarine ecosystem of the eastern and western gulfs of theArabian Sea and the Red Sea owing to anthropogenic inter-ference [29ndash32] Since 1990s 40 of the coasts of the PersianGulf have been modified [33] The Persian Gulf and the Red

2 International Journal of Oceanography

Sea areas have been reported to be warming rapidly owingto the developmental projects undertaken in the surroundingcoastal countries [30ndash32] The Gulf of Kutch on the Indiancoast is being aggressively developed as oil importing basesbecause of its proximity to the Middle East countries [29]In general the issues of common concern in the eastern andwestern gulfs of the Arabian Sea and the Red Sea includevarious anthropogenic activities like industrialization coastalinfrastructure development projects setting up of new portsand oil terminals oil pollution from shipping industryoverfishing dredging and increase in tourism and recre-ational activities [29ndash32 34] resulting in habitat destructionchanges in temperature and salinity profile and causing asignificant loss of biodiversity [35]

In this regard the present work was taken up to studythe monthly seasonal and annual pattern of Sea SurfaceTemperature (SST) and to analyse its changing pattern withemphasis on interannual variability in the eastern (Gulf ofKutch and Gulf of Khambhat) and the western gulfs (PersianGulf Gulf of Oman andGulf of Aden) of theArabian Sea andthe Red sea

2 Materials and Methods

21 Area of Study The gulfs of the Arabian Sea basin(Figure 1(a)) can be grouped into the eastern and the westernbranches The eastern branch includes the Gulf of Kutch andthe Gulf of Khambhat on the Indian coast whereas the west-ern branch includes the Gulf of Oman and the Persian Gulf inthe northwestern part of Arabian Sea and the Gulf of Adenin the southwestern part of Arabian Sea connecting it withthe Red Sea

211 Persian Gulf The Persian Gulf (24ndash3∘N 48ndash565∘E)(Figure 1(b)) located in an arid subtropical zone is a semien-closed shallow marginal sea with an average water depth of36m It is spread over an area of 239000 km2 and is 990 kmin length It is connected to the Gulf of Oman through the56 km wide Strait of Hormuz [36]

In the Persian Gulf the seasonal differences of insolationalongwith coldwinds from the nearby highlands result in ex-treme temperature (ranging from 16∘C to 35∘C) [36] and sa-linity (ranging from 36 to 43 parts per thousand) conditions[37] However despite the extreme conditions the offshorewaters of the Persian Gulf are rich in nutrients and support avariety of marine photoautotroph like the macroalgae phy-toplankton mangroves sea grass beds and intertidal vegeta-tion [25]

212 Gulf of Oman The Gulf of Oman (22∘3ndash26∘51015840N 565ndash61∘431015840E) is a strait connecting the Arabian Sea with the Per-sian Gulf (Figure 1(c))The Gulf of Oman is 320 kmwide and560 km long

Some of the most powerful eddy currents of the ArabianSea are located close to the Omani coast The coastal areas ofthe Gulf of Oman support varied habitats including man-grove swamps lagoons and mudflats

213 Gulf of Aden The Gulf of Aden (GA) (10∘ndash15∘N 43∘ndash52∘E) connecting the Red Sea with the Arabian Sea is partof the Suez Canal shipping route between the MediterraneanSea and the Indian Ocean (Figure 1(d)) It is about 900 kmlong with average depth of 1800m and covers an area ofabout 220 times 103 km2 Its importance lies in the fact that itprovides an outlet to the saline water masses of the Red Seainto the Arabian Sea [38]

214 Red Sea TheRed Sea (RS) (12∘291015840Nndash27∘571015840N 34∘361015840Endash43∘301015840E) is approximately 2100 km long and 280 km wide(Figure 1(e)) The average depth is about 500m but at placesit is more than 2000m deep The Red Sea is linked to theMediterranean Sea by the Suez Canal in the north whereas inthe south it is connected to the Arabian Sea through the Gulfof Aden

The waters of the Red Sea are warm and saline Thetemperature ranges from 21∘Cndash28∘C in the north and 26∘C to32∘C in the south Salinities in the Red Sea range from 37in the south to 42 in the north A consequence of theseextreme conditions is that some species within the Red Sea(like mangroves shallow sea grasses etc) probably exist atthe limits of their physiological tolerance [30]

215 Gulf of Kutch The Gulf of Kutch (22∘151015840ndash23∘41015840N68∘201015840ndash70∘401015840E) encloses an area of 7350 km2 (Figure 1(f))Towards the western end the Gulf is about 75 km wide and60m deep while in the eastern end it is 18 km wide and lessthan 20m deep It is under the influence of strong tidal cur-rents High rate of evaporation along with the release of saltywater from the adjoining saltpans of Rann of Kutch makesthe eastern part of the Gulf of Kutch more saline (40) thanthe western part (35) The temperature of the Gulf watersvaries between 24∘C to 30∘C

The Gulf of Kutch is one of Indiarsquos only coastal areasendowed with coral reefs It provides a platform for differenthabitats like coral reefs mangroves creeks mud flats islandsrocky shore sandy shore and so forth and hence is enrichedin biodiversity [29]

216 Gulf of Khambhat Gulf of Khambhat (between 72∘21015840Eto 72∘61015840E and 21∘ to 22∘21015840N) is one of the major fishing areasalong western coast of India (Figure 1(f)) It is about 80 kmwide at mouth and tapers to 25 km along the coast It isabout 140 km in length and is characterised by several inletsand creeks formed by the confluence of rivers The Gulf ofKhambhat is shallow with about 30m average depth andabounds in shoals and sandbanks It is known for its extremetidesThe tidal range at Gulf of Khambhat is known to be oneof the largest along the Indian coastline [39]

22 Data Used The regional effect of the global warmingin the oceanic water masses needs to be assessed andquantified However the lack of uniform data and method-ology hampers such regional analysis [1] With the avail-ability of National Oceanic and Atmospheric Administra-tionrsquos (NOAA) Advanced Very High Resolution Radiometer

International Journal of Oceanography 3

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

28∘28998400N28∘28998400N

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

(a)

48∘36998400E 56∘42998400E52∘4998400E

48∘36998400E 56∘42998400E52∘4998400E

28∘21998400N

24∘18998400E

28∘21998400N

57∘24998400E

(b)

57∘24998400E 59∘27998400E

57∘24998400E 59∘27998400E

26∘4998400N

24∘4998400N

22∘4998400N

26∘4998400N

24∘4998400N

22∘4998400N

(c)

45∘E 48∘E 51∘E

45∘E 48∘E 51∘E

12∘E

15∘E

12∘E

15∘E

(d)

35∘35998400E 40∘40998400E

35∘35998400E 40∘40998400E

25∘25998400E

20∘20998400E

15∘15998400E

25∘25998400E

20∘20998400E

15∘15998400E

(e)

Figure 1 Continued

4 International Journal of Oceanography

698∘E 711∘E

698∘E 711∘E

202∘N

2222∘N

202∘N

2222∘N

(f)

Figure 1 (a) Area of Study showing Arabian Sea basin (b) Persian Gulf (c) Gulf of Oman (d) Gulf of Aden (e) Red Sea (f) Gulf of Kutchand Gulf of Khambhat

(AVHRR) satellite data set for 25 years of span (1985ndash2009)to some extent the problem of uniformity of data has beensolved Besides the high resolution satellite derived SST datagives better results than in situ data in terms of its continuityand spatial coverage Even thoughReynolds SST andNationalCenter for Environmental Prediction (NCEP) reanalyzeddata sets [40] are available for longer periods but their lowspatial resolution (1∘ and 25∘ resp) and interpolation andreanalysismethods do not accurately capture the coastal areasand the upwelling regions [41]

In this study the monthly NOAA AVHRR Pathfinder(version 50) SST data at 4 km resolution was obtained fromNASArsquoS Jet Propulsion Laboratoryrsquos Physical OceanographicCentre (httppodaacjplnasagov) for the period 1985ndash2009 for climatological study of the eastern andwestern gulfsof the Arabian Sea and the Red Sea SST fields were derivedthrough theMultichannel Sea Surface Temperature (MCSST)algorithm as given by McClain [42]

23 Methodology For each of the defined areas of study themonthly images were masked to avoid the influence of theland and clouds using the image processing software ENVI 41and ERDAS 90 For analysis all the pixels of the study areawere included Care was taken to exclude the pixels with zerovalues while averaging Following Joint Global Ocean FluxStudy (JGOFS) [43] the four climatological seasons de-scribed here are

(a) northeast monsoon (DecemberndashMarch) (NEM)(b) spring intermonsoon (April-May) (SIM)(c) southwest monsoon (JunendashSeptember) (SWM) and(d) fall intermonsoon (October-November) (FIM)

The climatological mean (CM25) of 25 years (1985ndash2009)

for each month was calculated by averaging the monthly

mean (119872119910(119894)

) The interannual variability was analyzed usingthemonthly normalized anomalies computed by subtractingthe monthly climatological mean (CM

25) from the monthly

mean (119872119910(119894)

) of each year and normalized to the standarddeviation for that month (SD

25) and given as

119872(NA) =119872119910(119894)minus CM

25

SD25

(1)

The seasonal and annual normalized anomalies were com-puted by averaging the monthly normalized anomalies overappropriate seasons and years Coefficient of variation (CV)was used to express the magnitude of interannual variabilityin the annual and the seasonal SST for the eastern and thewestern gulfs of the Arabian Sea and the Red sea [44] and iscalculated as

CV = Standard DeviationMean

times 100 (2)

To study the effect of El Nino and La Nina comparison withENSO (El Nino-Southern Oscillation) was carried out usingthe multivariate ENSO index that is MEI index provided bythe climate diagnostic centre (httpwwwcdcnoaagov)

3 Results

31 Comparison of the Monthly Climatological Mean SST(1985ndash2009) Figure 2 shows the comparative analysis of themonthly climatological mean SST (1985ndash2009) of the easternand western gulfs of the Arabian Sea and the Red SeaThe SST in the Arabian Sea open ocean varies in a typicalbimodal pattern with warming during spring inter monsoon(SIM) (April-May) and fall intermonsoon (FIM) (October-November) and cooling during the southwest monsoon(SWM) (JunendashSeptember) and northeast monsoon (NEM)(DecemberndashMarch) seasons [45ndash47]

International Journal of Oceanography 5

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Persian GulfAS-open ocean

(a)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of OmanAS-open ocean

(b)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Red SeaAS-open ocean

(c)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of AdenAS-open ocean

(d)

Gulf of KutchAS-open ocean

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

(e)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of KhambhatAS-open ocean

(f)

Figure 2 Comparison of the monthly climatological mean SST (1985ndash2009) of the Persian Gulf Gulf of Oman Red Sea Gulf of Aden Gulfof Kutch and Gulf of Khambhat with Arabian Sea open ocean

TheGulf of Aden and the eastern gulfs of the Arabian Seanamely Gulf of Kutch and Gulf of Khambhat followed thetypical bimodal SST pattern as in the Arabian Sea Howeverunlike the Arabian Sea open ocean where the minimumSST is observed during the months of July-August (SWMseason) the minimum SST in these gulfs was found in themonth of January (NEM season) In the bimodal pattern theobserved second peak of SST in the Gulf of Kutch and Gulfof Khambhat was in the month of October similar to theArabian Sea open ocean pattern but in the Gulf of Aden the

second peak of SST was observed in the month of SeptemberClimatologically from November to April Gulf of Aden wascooler than the Arabian Sea open ocean (by an average 1∘C)while from May to October it was warmer than the ArabianSea open ocean (by an average 202∘C) Climatologically boththe eastern gulfs were cooler than theArabian Sea open ocean(by an average difference of 132∘C and 038∘C resp) forall the months except for September and October Besidesin the months of July and August Gulf of Kutch was foundto be cooler than Arabian Sea open ocean months by more

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearPersian Gulf

minus05

minus1

minus15

119910 = 00406119909 minus 8091

(a)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Oman

minus05

minus1

minus15

119910 = 00337119909 minus 67342

(b)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearRed Sea

minus05

minus1

minus15

119910 = 00643119909 minus 12848

(c)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Aden

119910 = 00377119909 minus 75329

minus15

minus1

minus05

(d)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Kutch

minus05

minus1

minus15

119910 = 00196119909 minus 39098

(e)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Khambhat

minus1Nor

mal

ized

anom

aly

minus05

minus15

119910 = 00104119909 minus 20676

(f)

Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

0123

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Red Sea

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Aden

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Kutch

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Khambhat

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

(a) NEM

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Red Sea

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Aden

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Kutch

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Khambhat

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

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mal

ized

anom

aly

(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

0123

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minus3minus2minus1

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minus3minus2minus1

0123

0123

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0123

119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

119910 = 00149119909 minus 29735

119910 = 0077119909 minus 15376

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mal

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(c) SWM

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minus3minus2minus1

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0123

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0

minus3minus2minus1

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119910 = 0066119909 minus 13179

y = 00414x minus 82738

y = 00256x minus 5108

y = 00418x minus 83488y = 00684x minus 1365

y = 00411x minus 82048

Nor

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

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1995

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1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

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1997

1998

1999

2000

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2003

2004

2005

2006

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2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

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1995

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1997

1998

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2003

2004

2005

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2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

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1994

1995

1996

1997

1998

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2003

2004

2005

2006

2007

2008

2009N

orm

aliz

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omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

2 International Journal of Oceanography

Sea areas have been reported to be warming rapidly owingto the developmental projects undertaken in the surroundingcoastal countries [30ndash32] The Gulf of Kutch on the Indiancoast is being aggressively developed as oil importing basesbecause of its proximity to the Middle East countries [29]In general the issues of common concern in the eastern andwestern gulfs of the Arabian Sea and the Red Sea includevarious anthropogenic activities like industrialization coastalinfrastructure development projects setting up of new portsand oil terminals oil pollution from shipping industryoverfishing dredging and increase in tourism and recre-ational activities [29ndash32 34] resulting in habitat destructionchanges in temperature and salinity profile and causing asignificant loss of biodiversity [35]

In this regard the present work was taken up to studythe monthly seasonal and annual pattern of Sea SurfaceTemperature (SST) and to analyse its changing pattern withemphasis on interannual variability in the eastern (Gulf ofKutch and Gulf of Khambhat) and the western gulfs (PersianGulf Gulf of Oman andGulf of Aden) of theArabian Sea andthe Red sea

2 Materials and Methods

21 Area of Study The gulfs of the Arabian Sea basin(Figure 1(a)) can be grouped into the eastern and the westernbranches The eastern branch includes the Gulf of Kutch andthe Gulf of Khambhat on the Indian coast whereas the west-ern branch includes the Gulf of Oman and the Persian Gulf inthe northwestern part of Arabian Sea and the Gulf of Adenin the southwestern part of Arabian Sea connecting it withthe Red Sea

211 Persian Gulf The Persian Gulf (24ndash3∘N 48ndash565∘E)(Figure 1(b)) located in an arid subtropical zone is a semien-closed shallow marginal sea with an average water depth of36m It is spread over an area of 239000 km2 and is 990 kmin length It is connected to the Gulf of Oman through the56 km wide Strait of Hormuz [36]

In the Persian Gulf the seasonal differences of insolationalongwith coldwinds from the nearby highlands result in ex-treme temperature (ranging from 16∘C to 35∘C) [36] and sa-linity (ranging from 36 to 43 parts per thousand) conditions[37] However despite the extreme conditions the offshorewaters of the Persian Gulf are rich in nutrients and support avariety of marine photoautotroph like the macroalgae phy-toplankton mangroves sea grass beds and intertidal vegeta-tion [25]

212 Gulf of Oman The Gulf of Oman (22∘3ndash26∘51015840N 565ndash61∘431015840E) is a strait connecting the Arabian Sea with the Per-sian Gulf (Figure 1(c))The Gulf of Oman is 320 kmwide and560 km long

Some of the most powerful eddy currents of the ArabianSea are located close to the Omani coast The coastal areas ofthe Gulf of Oman support varied habitats including man-grove swamps lagoons and mudflats

213 Gulf of Aden The Gulf of Aden (GA) (10∘ndash15∘N 43∘ndash52∘E) connecting the Red Sea with the Arabian Sea is partof the Suez Canal shipping route between the MediterraneanSea and the Indian Ocean (Figure 1(d)) It is about 900 kmlong with average depth of 1800m and covers an area ofabout 220 times 103 km2 Its importance lies in the fact that itprovides an outlet to the saline water masses of the Red Seainto the Arabian Sea [38]

214 Red Sea TheRed Sea (RS) (12∘291015840Nndash27∘571015840N 34∘361015840Endash43∘301015840E) is approximately 2100 km long and 280 km wide(Figure 1(e)) The average depth is about 500m but at placesit is more than 2000m deep The Red Sea is linked to theMediterranean Sea by the Suez Canal in the north whereas inthe south it is connected to the Arabian Sea through the Gulfof Aden

The waters of the Red Sea are warm and saline Thetemperature ranges from 21∘Cndash28∘C in the north and 26∘C to32∘C in the south Salinities in the Red Sea range from 37in the south to 42 in the north A consequence of theseextreme conditions is that some species within the Red Sea(like mangroves shallow sea grasses etc) probably exist atthe limits of their physiological tolerance [30]

215 Gulf of Kutch The Gulf of Kutch (22∘151015840ndash23∘41015840N68∘201015840ndash70∘401015840E) encloses an area of 7350 km2 (Figure 1(f))Towards the western end the Gulf is about 75 km wide and60m deep while in the eastern end it is 18 km wide and lessthan 20m deep It is under the influence of strong tidal cur-rents High rate of evaporation along with the release of saltywater from the adjoining saltpans of Rann of Kutch makesthe eastern part of the Gulf of Kutch more saline (40) thanthe western part (35) The temperature of the Gulf watersvaries between 24∘C to 30∘C

The Gulf of Kutch is one of Indiarsquos only coastal areasendowed with coral reefs It provides a platform for differenthabitats like coral reefs mangroves creeks mud flats islandsrocky shore sandy shore and so forth and hence is enrichedin biodiversity [29]

216 Gulf of Khambhat Gulf of Khambhat (between 72∘21015840Eto 72∘61015840E and 21∘ to 22∘21015840N) is one of the major fishing areasalong western coast of India (Figure 1(f)) It is about 80 kmwide at mouth and tapers to 25 km along the coast It isabout 140 km in length and is characterised by several inletsand creeks formed by the confluence of rivers The Gulf ofKhambhat is shallow with about 30m average depth andabounds in shoals and sandbanks It is known for its extremetidesThe tidal range at Gulf of Khambhat is known to be oneof the largest along the Indian coastline [39]

22 Data Used The regional effect of the global warmingin the oceanic water masses needs to be assessed andquantified However the lack of uniform data and method-ology hampers such regional analysis [1] With the avail-ability of National Oceanic and Atmospheric Administra-tionrsquos (NOAA) Advanced Very High Resolution Radiometer

International Journal of Oceanography 3

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

28∘28998400N28∘28998400N

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

(a)

48∘36998400E 56∘42998400E52∘4998400E

48∘36998400E 56∘42998400E52∘4998400E

28∘21998400N

24∘18998400E

28∘21998400N

57∘24998400E

(b)

57∘24998400E 59∘27998400E

57∘24998400E 59∘27998400E

26∘4998400N

24∘4998400N

22∘4998400N

26∘4998400N

24∘4998400N

22∘4998400N

(c)

45∘E 48∘E 51∘E

45∘E 48∘E 51∘E

12∘E

15∘E

12∘E

15∘E

(d)

35∘35998400E 40∘40998400E

35∘35998400E 40∘40998400E

25∘25998400E

20∘20998400E

15∘15998400E

25∘25998400E

20∘20998400E

15∘15998400E

(e)

Figure 1 Continued

4 International Journal of Oceanography

698∘E 711∘E

698∘E 711∘E

202∘N

2222∘N

202∘N

2222∘N

(f)

Figure 1 (a) Area of Study showing Arabian Sea basin (b) Persian Gulf (c) Gulf of Oman (d) Gulf of Aden (e) Red Sea (f) Gulf of Kutchand Gulf of Khambhat

(AVHRR) satellite data set for 25 years of span (1985ndash2009)to some extent the problem of uniformity of data has beensolved Besides the high resolution satellite derived SST datagives better results than in situ data in terms of its continuityand spatial coverage Even thoughReynolds SST andNationalCenter for Environmental Prediction (NCEP) reanalyzeddata sets [40] are available for longer periods but their lowspatial resolution (1∘ and 25∘ resp) and interpolation andreanalysismethods do not accurately capture the coastal areasand the upwelling regions [41]

In this study the monthly NOAA AVHRR Pathfinder(version 50) SST data at 4 km resolution was obtained fromNASArsquoS Jet Propulsion Laboratoryrsquos Physical OceanographicCentre (httppodaacjplnasagov) for the period 1985ndash2009 for climatological study of the eastern andwestern gulfsof the Arabian Sea and the Red Sea SST fields were derivedthrough theMultichannel Sea Surface Temperature (MCSST)algorithm as given by McClain [42]

23 Methodology For each of the defined areas of study themonthly images were masked to avoid the influence of theland and clouds using the image processing software ENVI 41and ERDAS 90 For analysis all the pixels of the study areawere included Care was taken to exclude the pixels with zerovalues while averaging Following Joint Global Ocean FluxStudy (JGOFS) [43] the four climatological seasons de-scribed here are

(a) northeast monsoon (DecemberndashMarch) (NEM)(b) spring intermonsoon (April-May) (SIM)(c) southwest monsoon (JunendashSeptember) (SWM) and(d) fall intermonsoon (October-November) (FIM)

The climatological mean (CM25) of 25 years (1985ndash2009)

for each month was calculated by averaging the monthly

mean (119872119910(119894)

) The interannual variability was analyzed usingthemonthly normalized anomalies computed by subtractingthe monthly climatological mean (CM

25) from the monthly

mean (119872119910(119894)

) of each year and normalized to the standarddeviation for that month (SD

25) and given as

119872(NA) =119872119910(119894)minus CM

25

SD25

(1)

The seasonal and annual normalized anomalies were com-puted by averaging the monthly normalized anomalies overappropriate seasons and years Coefficient of variation (CV)was used to express the magnitude of interannual variabilityin the annual and the seasonal SST for the eastern and thewestern gulfs of the Arabian Sea and the Red sea [44] and iscalculated as

CV = Standard DeviationMean

times 100 (2)

To study the effect of El Nino and La Nina comparison withENSO (El Nino-Southern Oscillation) was carried out usingthe multivariate ENSO index that is MEI index provided bythe climate diagnostic centre (httpwwwcdcnoaagov)

3 Results

31 Comparison of the Monthly Climatological Mean SST(1985ndash2009) Figure 2 shows the comparative analysis of themonthly climatological mean SST (1985ndash2009) of the easternand western gulfs of the Arabian Sea and the Red SeaThe SST in the Arabian Sea open ocean varies in a typicalbimodal pattern with warming during spring inter monsoon(SIM) (April-May) and fall intermonsoon (FIM) (October-November) and cooling during the southwest monsoon(SWM) (JunendashSeptember) and northeast monsoon (NEM)(DecemberndashMarch) seasons [45ndash47]

International Journal of Oceanography 5

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Persian GulfAS-open ocean

(a)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of OmanAS-open ocean

(b)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Red SeaAS-open ocean

(c)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of AdenAS-open ocean

(d)

Gulf of KutchAS-open ocean

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

(e)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of KhambhatAS-open ocean

(f)

Figure 2 Comparison of the monthly climatological mean SST (1985ndash2009) of the Persian Gulf Gulf of Oman Red Sea Gulf of Aden Gulfof Kutch and Gulf of Khambhat with Arabian Sea open ocean

TheGulf of Aden and the eastern gulfs of the Arabian Seanamely Gulf of Kutch and Gulf of Khambhat followed thetypical bimodal SST pattern as in the Arabian Sea Howeverunlike the Arabian Sea open ocean where the minimumSST is observed during the months of July-August (SWMseason) the minimum SST in these gulfs was found in themonth of January (NEM season) In the bimodal pattern theobserved second peak of SST in the Gulf of Kutch and Gulfof Khambhat was in the month of October similar to theArabian Sea open ocean pattern but in the Gulf of Aden the

second peak of SST was observed in the month of SeptemberClimatologically from November to April Gulf of Aden wascooler than the Arabian Sea open ocean (by an average 1∘C)while from May to October it was warmer than the ArabianSea open ocean (by an average 202∘C) Climatologically boththe eastern gulfs were cooler than theArabian Sea open ocean(by an average difference of 132∘C and 038∘C resp) forall the months except for September and October Besidesin the months of July and August Gulf of Kutch was foundto be cooler than Arabian Sea open ocean months by more

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

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Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

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119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

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(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

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Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

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Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

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Applied ampEnvironmentalSoil Science

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Mining

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Journal of

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OceanographyInternational Journal of

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Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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MineralogyInternational Journal of

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Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

International Journal of Oceanography 3

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

35∘35998400E 42∘42998400E 49∘49998400E 56∘56998400E 64∘3998400E 71∘10998400E 78∘17998400E

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

28∘28998400N28∘28998400N

21∘21998400N

14∘14998400N

7∘7998400N

0∘N

7∘7998400S

(a)

48∘36998400E 56∘42998400E52∘4998400E

48∘36998400E 56∘42998400E52∘4998400E

28∘21998400N

24∘18998400E

28∘21998400N

57∘24998400E

(b)

57∘24998400E 59∘27998400E

57∘24998400E 59∘27998400E

26∘4998400N

24∘4998400N

22∘4998400N

26∘4998400N

24∘4998400N

22∘4998400N

(c)

45∘E 48∘E 51∘E

45∘E 48∘E 51∘E

12∘E

15∘E

12∘E

15∘E

(d)

35∘35998400E 40∘40998400E

35∘35998400E 40∘40998400E

25∘25998400E

20∘20998400E

15∘15998400E

25∘25998400E

20∘20998400E

15∘15998400E

(e)

Figure 1 Continued

4 International Journal of Oceanography

698∘E 711∘E

698∘E 711∘E

202∘N

2222∘N

202∘N

2222∘N

(f)

Figure 1 (a) Area of Study showing Arabian Sea basin (b) Persian Gulf (c) Gulf of Oman (d) Gulf of Aden (e) Red Sea (f) Gulf of Kutchand Gulf of Khambhat

(AVHRR) satellite data set for 25 years of span (1985ndash2009)to some extent the problem of uniformity of data has beensolved Besides the high resolution satellite derived SST datagives better results than in situ data in terms of its continuityand spatial coverage Even thoughReynolds SST andNationalCenter for Environmental Prediction (NCEP) reanalyzeddata sets [40] are available for longer periods but their lowspatial resolution (1∘ and 25∘ resp) and interpolation andreanalysismethods do not accurately capture the coastal areasand the upwelling regions [41]

In this study the monthly NOAA AVHRR Pathfinder(version 50) SST data at 4 km resolution was obtained fromNASArsquoS Jet Propulsion Laboratoryrsquos Physical OceanographicCentre (httppodaacjplnasagov) for the period 1985ndash2009 for climatological study of the eastern andwestern gulfsof the Arabian Sea and the Red Sea SST fields were derivedthrough theMultichannel Sea Surface Temperature (MCSST)algorithm as given by McClain [42]

23 Methodology For each of the defined areas of study themonthly images were masked to avoid the influence of theland and clouds using the image processing software ENVI 41and ERDAS 90 For analysis all the pixels of the study areawere included Care was taken to exclude the pixels with zerovalues while averaging Following Joint Global Ocean FluxStudy (JGOFS) [43] the four climatological seasons de-scribed here are

(a) northeast monsoon (DecemberndashMarch) (NEM)(b) spring intermonsoon (April-May) (SIM)(c) southwest monsoon (JunendashSeptember) (SWM) and(d) fall intermonsoon (October-November) (FIM)

The climatological mean (CM25) of 25 years (1985ndash2009)

for each month was calculated by averaging the monthly

mean (119872119910(119894)

) The interannual variability was analyzed usingthemonthly normalized anomalies computed by subtractingthe monthly climatological mean (CM

25) from the monthly

mean (119872119910(119894)

) of each year and normalized to the standarddeviation for that month (SD

25) and given as

119872(NA) =119872119910(119894)minus CM

25

SD25

(1)

The seasonal and annual normalized anomalies were com-puted by averaging the monthly normalized anomalies overappropriate seasons and years Coefficient of variation (CV)was used to express the magnitude of interannual variabilityin the annual and the seasonal SST for the eastern and thewestern gulfs of the Arabian Sea and the Red sea [44] and iscalculated as

CV = Standard DeviationMean

times 100 (2)

To study the effect of El Nino and La Nina comparison withENSO (El Nino-Southern Oscillation) was carried out usingthe multivariate ENSO index that is MEI index provided bythe climate diagnostic centre (httpwwwcdcnoaagov)

3 Results

31 Comparison of the Monthly Climatological Mean SST(1985ndash2009) Figure 2 shows the comparative analysis of themonthly climatological mean SST (1985ndash2009) of the easternand western gulfs of the Arabian Sea and the Red SeaThe SST in the Arabian Sea open ocean varies in a typicalbimodal pattern with warming during spring inter monsoon(SIM) (April-May) and fall intermonsoon (FIM) (October-November) and cooling during the southwest monsoon(SWM) (JunendashSeptember) and northeast monsoon (NEM)(DecemberndashMarch) seasons [45ndash47]

International Journal of Oceanography 5

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Persian GulfAS-open ocean

(a)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of OmanAS-open ocean

(b)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Red SeaAS-open ocean

(c)

1921232527293133

Jan

Feb

Mar

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Figure 2 Comparison of the monthly climatological mean SST (1985ndash2009) of the Persian Gulf Gulf of Oman Red Sea Gulf of Aden Gulfof Kutch and Gulf of Khambhat with Arabian Sea open ocean

TheGulf of Aden and the eastern gulfs of the Arabian Seanamely Gulf of Kutch and Gulf of Khambhat followed thetypical bimodal SST pattern as in the Arabian Sea Howeverunlike the Arabian Sea open ocean where the minimumSST is observed during the months of July-August (SWMseason) the minimum SST in these gulfs was found in themonth of January (NEM season) In the bimodal pattern theobserved second peak of SST in the Gulf of Kutch and Gulfof Khambhat was in the month of October similar to theArabian Sea open ocean pattern but in the Gulf of Aden the

second peak of SST was observed in the month of SeptemberClimatologically from November to April Gulf of Aden wascooler than the Arabian Sea open ocean (by an average 1∘C)while from May to October it was warmer than the ArabianSea open ocean (by an average 202∘C) Climatologically boththe eastern gulfs were cooler than theArabian Sea open ocean(by an average difference of 132∘C and 038∘C resp) forall the months except for September and October Besidesin the months of July and August Gulf of Kutch was foundto be cooler than Arabian Sea open ocean months by more

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

0

05

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15

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minus1Nor

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minus05

minus15

119910 = 00104119909 minus 20676

(f)

Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

0123

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minus1minus2minus3

0123

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0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

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(a) NEM

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119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

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(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

0123

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minus3minus2minus1

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minus3minus2minus1

0123

0123

0123

0123

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119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

119910 = 00149119909 minus 29735

119910 = 0077119909 minus 15376

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y = minus00249x + 49629y = minus00211x + 42057

(c) SWM

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119910 = 0066119909 minus 13179

y = 00414x minus 82738

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y = 00418x minus 83488y = 00684x minus 1365

y = 00411x minus 82048

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

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1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geological ResearchJournal of

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Geology Advances in

4 International Journal of Oceanography

698∘E 711∘E

698∘E 711∘E

202∘N

2222∘N

202∘N

2222∘N

(f)

Figure 1 (a) Area of Study showing Arabian Sea basin (b) Persian Gulf (c) Gulf of Oman (d) Gulf of Aden (e) Red Sea (f) Gulf of Kutchand Gulf of Khambhat

(AVHRR) satellite data set for 25 years of span (1985ndash2009)to some extent the problem of uniformity of data has beensolved Besides the high resolution satellite derived SST datagives better results than in situ data in terms of its continuityand spatial coverage Even thoughReynolds SST andNationalCenter for Environmental Prediction (NCEP) reanalyzeddata sets [40] are available for longer periods but their lowspatial resolution (1∘ and 25∘ resp) and interpolation andreanalysismethods do not accurately capture the coastal areasand the upwelling regions [41]

In this study the monthly NOAA AVHRR Pathfinder(version 50) SST data at 4 km resolution was obtained fromNASArsquoS Jet Propulsion Laboratoryrsquos Physical OceanographicCentre (httppodaacjplnasagov) for the period 1985ndash2009 for climatological study of the eastern andwestern gulfsof the Arabian Sea and the Red Sea SST fields were derivedthrough theMultichannel Sea Surface Temperature (MCSST)algorithm as given by McClain [42]

23 Methodology For each of the defined areas of study themonthly images were masked to avoid the influence of theland and clouds using the image processing software ENVI 41and ERDAS 90 For analysis all the pixels of the study areawere included Care was taken to exclude the pixels with zerovalues while averaging Following Joint Global Ocean FluxStudy (JGOFS) [43] the four climatological seasons de-scribed here are

(a) northeast monsoon (DecemberndashMarch) (NEM)(b) spring intermonsoon (April-May) (SIM)(c) southwest monsoon (JunendashSeptember) (SWM) and(d) fall intermonsoon (October-November) (FIM)

The climatological mean (CM25) of 25 years (1985ndash2009)

for each month was calculated by averaging the monthly

mean (119872119910(119894)

) The interannual variability was analyzed usingthemonthly normalized anomalies computed by subtractingthe monthly climatological mean (CM

25) from the monthly

mean (119872119910(119894)

) of each year and normalized to the standarddeviation for that month (SD

25) and given as

119872(NA) =119872119910(119894)minus CM

25

SD25

(1)

The seasonal and annual normalized anomalies were com-puted by averaging the monthly normalized anomalies overappropriate seasons and years Coefficient of variation (CV)was used to express the magnitude of interannual variabilityin the annual and the seasonal SST for the eastern and thewestern gulfs of the Arabian Sea and the Red sea [44] and iscalculated as

CV = Standard DeviationMean

times 100 (2)

To study the effect of El Nino and La Nina comparison withENSO (El Nino-Southern Oscillation) was carried out usingthe multivariate ENSO index that is MEI index provided bythe climate diagnostic centre (httpwwwcdcnoaagov)

3 Results

31 Comparison of the Monthly Climatological Mean SST(1985ndash2009) Figure 2 shows the comparative analysis of themonthly climatological mean SST (1985ndash2009) of the easternand western gulfs of the Arabian Sea and the Red SeaThe SST in the Arabian Sea open ocean varies in a typicalbimodal pattern with warming during spring inter monsoon(SIM) (April-May) and fall intermonsoon (FIM) (October-November) and cooling during the southwest monsoon(SWM) (JunendashSeptember) and northeast monsoon (NEM)(DecemberndashMarch) seasons [45ndash47]

International Journal of Oceanography 5

1921232527293133

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Figure 2 Comparison of the monthly climatological mean SST (1985ndash2009) of the Persian Gulf Gulf of Oman Red Sea Gulf of Aden Gulfof Kutch and Gulf of Khambhat with Arabian Sea open ocean

TheGulf of Aden and the eastern gulfs of the Arabian Seanamely Gulf of Kutch and Gulf of Khambhat followed thetypical bimodal SST pattern as in the Arabian Sea Howeverunlike the Arabian Sea open ocean where the minimumSST is observed during the months of July-August (SWMseason) the minimum SST in these gulfs was found in themonth of January (NEM season) In the bimodal pattern theobserved second peak of SST in the Gulf of Kutch and Gulfof Khambhat was in the month of October similar to theArabian Sea open ocean pattern but in the Gulf of Aden the

second peak of SST was observed in the month of SeptemberClimatologically from November to April Gulf of Aden wascooler than the Arabian Sea open ocean (by an average 1∘C)while from May to October it was warmer than the ArabianSea open ocean (by an average 202∘C) Climatologically boththe eastern gulfs were cooler than theArabian Sea open ocean(by an average difference of 132∘C and 038∘C resp) forall the months except for September and October Besidesin the months of July and August Gulf of Kutch was foundto be cooler than Arabian Sea open ocean months by more

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

0

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119910 = 00104119909 minus 20676

(f)

Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

0123

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minus1minus2minus3

0123

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0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

anom

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(a) NEM

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minus1minus2minus3

119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

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(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

0123

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0123

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119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

119910 = 00149119909 minus 29735

119910 = 0077119909 minus 15376

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(c) SWM

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119910 = 0066119909 minus 13179

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geological ResearchJournal of

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Geology Advances in

International Journal of Oceanography 5

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Persian GulfAS-open ocean

(a)

1921232527293133

Jan

Feb

Mar

Apr

May Jun Jul

Aug

Sep

Oct

Nov Dec

Month

Mea

n SS

T (∘

C)

Gulf of OmanAS-open ocean

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Figure 2 Comparison of the monthly climatological mean SST (1985ndash2009) of the Persian Gulf Gulf of Oman Red Sea Gulf of Aden Gulfof Kutch and Gulf of Khambhat with Arabian Sea open ocean

TheGulf of Aden and the eastern gulfs of the Arabian Seanamely Gulf of Kutch and Gulf of Khambhat followed thetypical bimodal SST pattern as in the Arabian Sea Howeverunlike the Arabian Sea open ocean where the minimumSST is observed during the months of July-August (SWMseason) the minimum SST in these gulfs was found in themonth of January (NEM season) In the bimodal pattern theobserved second peak of SST in the Gulf of Kutch and Gulfof Khambhat was in the month of October similar to theArabian Sea open ocean pattern but in the Gulf of Aden the

second peak of SST was observed in the month of SeptemberClimatologically from November to April Gulf of Aden wascooler than the Arabian Sea open ocean (by an average 1∘C)while from May to October it was warmer than the ArabianSea open ocean (by an average 202∘C) Climatologically boththe eastern gulfs were cooler than theArabian Sea open ocean(by an average difference of 132∘C and 038∘C resp) forall the months except for September and October Besidesin the months of July and August Gulf of Kutch was foundto be cooler than Arabian Sea open ocean months by more

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

0

05

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15

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119910 = 00104119909 minus 20676

(f)

Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

0123

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minus1minus2minus3

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minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

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(a) NEM

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119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

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(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

0123

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0123

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119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

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119910 = 0077119909 minus 15376

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(c) SWM

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119910 = 0066119909 minus 13179

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geology Advances in

6 International Journal of Oceanography

than 2∘C whereas in Gulf of Khambhat no such significantdifference was found

The Persian Gulf Gulf of Oman and the Red Seaexhibited a distinct unimodal SST curve instead of thetypical bimodal pattern as in the Arabian Sea open oceanwith minimum temperature during the NEM season andmaximum temperature during the SWMseasonWhereas theminimum temperature for these three water bodies was inFebruary the maximum temperature in the Persian Gulf andthe Red sea was in August whereas in the Gulf of Oman themaximum temperature was in the month of June Climato-logically from November to May the Persian Gulf Gulf ofOman and the Red sea were found to be cooler than theArabian Sea open ocean (by an average 49∘C 22∘C and19∘C resp) while from June to October they were warmerthan the Arabian Sea open ocean (by an average 37∘C 27∘Cand 208∘C resp) Amongst the eastern and western gulfs ofthe Arabian Sea and the Red Sea the Persian Gulf exhibitedthe highest range of SST (1197∘C)

32 Interannual Variability of SST in the Eastern and WesternGulfs of Arabian Sea and Red Sea from 1985 to 2009

321 Comparison of the Annual Normalized SST Anomalyfrom 1985 to 2009 A time series study of the interannual var-iability of SST can be seen from Figure 3 A warming trendwas observed in all the gulfs of the Arabian Sea in terms ofthe increasing annual normalized SST anomalies from 1985 to2009 Whereas in the eastern gulfs of the Arabian Sea theannual increase of normalised SST anomaly from 1985 to2009 was insignificant with the Gulf of Kutch and Gulfof Khambhat showing an increase of 019decade and01decade respectively in the western gulfs of the ArabianSea and the Red sea a sharp increase in SST was observedwith the maximum rate of increase of normalized SSTanomaly in the Red Sea (064decade) followed by the PersianGulf (04decade)

A remarkable time lag in the rise of annual SSTwas foundbetween the eastern and the western gulfs of the ArabianSea and the Red Sea For the western gulfs of the ArabianSea and the Red Sea a sharp increase in the annual SST wasobserved from 1992-1993 to 2009 However for the easterngulfs the warming was delayed till 1995 and hence instead of1992-1993 the sharp rise of annual SST was found from 1995onwards

For the Persian Gulf Gulf of Oman and Gulf of Adena decrease in annual normalized anomaly (cooling) wasobserved from 1985 to 1991 and thereafter from 1992 to 2009a sharp increase (warming) was found In the Persian Gulfthe normalized anomaly decreased (by minus161) from minus025 inthe 1985 to minus136 in 1991 and thereafter increased (by +148)to +012 in 2009 In the Gulf of Oman normalized anomalydecreased (by minus10) from minus044 (1985) to minus144 (1991) andlater increased (by +10) to +045 (2009) However in theRed Sea the normalized anomaly decreased from 1985 to1992 (instead of 1991) from minus076 (1985) to minus153 (1992) andthereafter increased to +064 (2009)

In the Gulf of Kutch and Gulf of Khambhat (eastern gulfsof the A rabian Sea) a significant decrease in normalizedanomaly (cooling) was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly (warming) was found In the Gulf of Kutch and Gulfof Khambhat the normalized anomaly decreased from minus010in 1985 to minus092 in 1994 and subsequently increased to +075in 2009 Similarly in the Gulf of Khambhat the normalizedanomaly decreased from minus022 in 1985 to minus075 in 1994 andlater increased to +058 in 2009

In the three western gulfs of the Arabian Sea namelyPersian Gulf Gulf of Oman and Gulf of Aden the maximumnegative normalized SST anomaly was observed in 1991(minus136 minus144 and minus116 resp) In the Red Sea the maximumnegative normalized SST anomaly was found in 1992 (minus15)On the other hand in both the eastern gulfs of the Ara-bian Sea maximum negative normalized SST anomaly wasobserved in 1994 (minus093 in Gulf of Kutch and minus075 in Gulf ofKhambhat)Themaximumpositive normalized SST anomalywas found to be in 1998 in Gulf of Aden (+154) in 1999 inPersian Gulf (+11) in 2001 in Red Sea (+11) and in 2002 inGulf of Gulf of Oman whereas in both the eastern gulfs ofthe Arabian Sea maximumpositive normalized anomaly wasobserved in 2007

In the western gulfs of Arabian Sea and the Red Sea theinfluence of the El Nino and the La Nina events can be seenfrom the crest and the troughs of the graph depicting theannual SST anomaly For instance the La Nina years like 19851986 1989 1996 1999 2000 and 2008 were found to havea high negative anomalies (cooling) and the El Nino yearslike 1986 1988 1991ndash1995 1997-1998 2002 2006 and 2009were observed to have a high positive normalized anomalies(warming) However the influence of the El Nino and LaNina varied in terms of the difference in magnitude of thepositive and negative anomalies Besides in the eastern gulfsof theArabian Sea only fewof the ElNino (namely 1987 19882002 and 2006) or La Nina (namely 1989 and 2008) eventsinfluenced the warming or cooling of the gulfs

322 Comparison of Seasonal Normalized SST Anomaly from1985ndash2009 The interannual variation of SST during the fourseasons namely northeast monsoon (NEM) (DecemberndashMarch) spring intermonsoon (SIM) (April-May) southwestMonsoon (SWM) (JunendashSeptember) and fall inter Monsoon(FIM) (October-November) affecting the gulfs of ArabianSea and the Red sea was analyzed using the normalized SSTanomaly indices as in Figure 4

As seen from Figures 4(a) 4(b) 4(c) and 4(d) a similarinterannual variation of SST pattern for the western gulfsof the Arabian Sea (namely Persian Gulf Gulf of Omanand Gulf of Aden) and the Red Sea was observed with anincreasing trend of SST in all the four seasons However inthe eastern gulfs (Gulf of Kutch and Gulf of Khambhat) anincreasing pattern of SST was found during the NEM SIMand FIM but during the SWM season cooling was observed

During the northeast monsoon (NEM) (DecemberndashMarch) (Figure 4(a)) the normalized SST anomaly increased(warming) in all eastern and western gulfs of the Arabian

International Journal of Oceanography 7

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Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

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119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

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(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

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aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

International Journal of Oceanography 7

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearPersian Gulf

minus05

minus1

minus15

119910 = 00406119909 minus 8091

(a)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Oman

minus05

minus1

minus15

119910 = 00337119909 minus 67342

(b)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearRed Sea

minus05

minus1

minus15

119910 = 00643119909 minus 12848

(c)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Aden

119910 = 00377119909 minus 75329

minus15

minus1

minus05

(d)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

anom

aly

YearGulf of Kutch

minus05

minus1

minus15

119910 = 00196119909 minus 39098

(e)

0

05

1

15

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Khambhat

minus1Nor

mal

ized

anom

aly

minus05

minus15

119910 = 00104119909 minus 20676

(f)

Figure 3 Comparison of the annual normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat

Sea and the Red Sea but the increase was more in thewestern gulfs and the Red Sea as compared to the easterngulfs with the maximum rate of increase of SST in the RedSea (055decade) A similar interannual variability patternduring the NEM season was observed in the Persian GulfGulf ofOman and theRed Sea on one hand andGulf ofAdenGulf of Kutch and Gulf of Khambhat on the other From1986 to 1992 in the Persian Gulf Gulf of Oman and the RedSea a decrease in SST anomalywas observed (cooling) whichwas followed by a phase of increasing SST anomaly (warm-ing) from 1992 to 1999 From 1999 to 2005 the SST anomaly

decreased substantially However from 2005 to 2009 again awarming phase with increasing SST anomaly was observedIn the year 1998-1999 an El Nino year a very high positiveSST anomalywas observed in thewestern gulfs of theArabianSea and the Red Sea The warming was remarkable as in thePersian Gulf and the Red Sea the positive anomaly reachedup to +205 and +138 respectively Even though the Gulf ofOman showed a high positive deviation of +15 from the cli-matological mean in 1999 but its maximumpositive anomaly(ie maximum warming) was observed during 2002 (+192)which was again an El Nino year Amongst the eastern gulfs

8 International Journal of Oceanography

0123

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Red Sea

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Aden

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Kutch

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Khambhat

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

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119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

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Figure 4 Continued

International Journal of Oceanography 9

0123

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(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

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Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

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Mining

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GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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MineralogyInternational Journal of

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Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

8 International Journal of Oceanography

0123

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Nor

mal

ized

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Red Sea

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Aden

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Kutch

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Khambhat

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00297119909 minus 59374 119910 = 00391119909 minus 78011

119910 = 00554119909 minus 11069 119910 = 00415119909 minus 82856

119910 = 00209119909 minus 41726 119910 = 0014119909 minus 27933

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

(a) NEM

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Red Sea

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Aden

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Kutch

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

YearGulf of Khambhat

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

0123

minus1minus2minus3

119910 = 00488119909 minus 97406 119910 = 00583119909 minus 11634

119910 = 00589119909 minus 11769

119910 = 00527119909 minus 10528 119910 = 00497119909 minus 99226

119910 = 00273119909 minus 54516

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

(b) SIM

Figure 4 Continued

International Journal of Oceanography 9

0123

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

Red Sea Gulf of Aden

Gulf of Kutch Gulf of Khambhat

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

0123

0123

0123

0123

0123

119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

119910 = 00149119909 minus 29735

119910 = 0077119909 minus 15376

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

y = minus00249x + 49629y = minus00211x + 42057

(c) SWM

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf Gulf of Oman

Red Sea Gulf of Aden

YearGulf of Kutch

YearGulf of Khambhat

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

0123

0123

0

minus3minus2minus1

0123

0123

0123

123

119910 = 0066119909 minus 13179

y = 00414x minus 82738

y = 00256x minus 5108

y = 00418x minus 83488y = 00684x minus 1365

y = 00411x minus 82048

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

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International Journal of Oceanography 9

0123

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Gulf of Oman

Red Sea Gulf of Aden

Gulf of Kutch Gulf of Khambhat

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

0123

0123

0123

0123

0123

119910 = 00518119909 minus 10308

119910 = 00377119909 minus 752

119910 = 00149119909 minus 29735

119910 = 0077119909 minus 15376

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

y = minus00249x + 49629y = minus00211x + 42057

(c) SWM

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Persian Gulf Gulf of Oman

Red Sea Gulf of Aden

YearGulf of Kutch

YearGulf of Khambhat

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

minus3minus2minus1

0123

0123

0

minus3minus2minus1

0123

0123

0123

123

119910 = 0066119909 minus 13179

y = 00414x minus 82738

y = 00256x minus 5108

y = 00418x minus 83488y = 00684x minus 1365

y = 00411x minus 82048

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

Nor

mal

ized

anom

aly

(d) FIM

Figure 4 Comparison of the seasonal normalised SST anomaly from 1985 to 2009 of the Persian Gulf Gulf of Oman Red Sea Gulf of AdenGulf of Kutch and Gulf of Khambhat (a) Northeast monsoon (NEM) (DecemberndashMarch) (b) spring intermonsoon (SIM) (April-May) (c)southwest monsoon (SWM) (JunendashSeptember) and (d) fall intermonsoon (FIM) (October-November)

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

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2008

2009N

orm

aliz

ed an

omal

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YearMeiGulf of Oman

(b)

0123

1985

1986

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1991

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1993

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1999

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2003

2004

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2007

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2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

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1989

1990

1991

1992

1993

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1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

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2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

10 International Journal of Oceanography

of the Arabian Sea and the Gulf of Aden a similar patternof interannual variation was observed wherein from 1986 to1990 the SST anomaly increased remarkably followed by aphase of decreasing SST anomaly from 1990 to 1995Howeverthis cooling phase got extended in theGulf of Aden up to 1997From 1995 to 2001-2002 the SST anomaly increased in thetwo eastern gulfs whereas in the Gulf of Aden the increasewas noticed up to 2003 From 2001-2002 (2003 in case ofGulf of Aden) to 2005 the SST anomaly again decreasedresulting in a cooling phase However from 2005 onwardslike the rest of the western gulfs of the Arabian Sea and theRed Sea a remarkable increase in SST anomaly was observedin the Gulf of Aden and the two eastern gulfs of the ArabianSea In the Gulf of Aden the maximum positive SST anomalywas in 1998 (+198) However in Gulf of Kutch themaximumpositive deviation from the climatological mean was notedduring 2001 (+147) whereas in Gulf of Khambhat it wasobserved to be during 2009 (+148) DuringNEM the PersianGulf Gulf of Oman and the Red Sea exhibited the maximumnegative deviation of SST from the climatological mean (iemaximum cooling) during 1992 (minus18 minus228 and minus229resp) whereas Gulf of Kutch and Khambhat showed themaximum negative deviation observed during 1995 (minus115and minus136 resp)

During the spring intermonsoon (SIM) (April-May)(Figure 4(b)) the normalized SST anomaly increased (warm-ing) in all the eastern and the western gulfs of the Arabian Seaand the Red Sea withmaximum increase in theGulf ofOmanand the Red Sea (at the rate of 058decade) It was observedthat from 2005 onwards during the SIM the normalized SSTanomalies increased substantially in the Persian Gulf Gulf ofOman Red Sea Gulf of Kutch and Gulf of Khambhat Theinterannual variability pattern of the eastern gulfs of theArabian Sea and the Gulf of Aden was found to be similarbeginning with a cooling phase (decreasing SST anomaly)from 1985 to 1991-1992 followed by awarming phase (increas-ing SST anomaly)which continued up to 1998Whereas in theGulf of Aden the next phase of coolingwas noticed from 1998till 2003 in the eastern gulfs a time lag of a year was foundwith Gulf of Kutch extending the period of cooling from 1998to 2004 and Gulf of Khambhat extending the period from1998 to 2005 In the eastern gulfs of the Arabian Sea themaximum positive deviation of SST from the climatologicalmean (ie maximum warming) during SIM was in 2002Amongst the rest of the western gulfs of the Arabian Seaand the Red Sea the pattern of interannual variability of SSTwas observed to be similar during the SIM In the PersianGulf Gulf of Oman and the Red Sea from 1985 to 1991-1992a cooling phase (with decreasing SST anomaly) was foundIt was followed by a decade of warming from 1991-1992 to2001 when the SST anomaly increased significantly In thesegulfs and the Red Sea from 2001 onwards till 2005 anothercooling phase was observed However in the last 5 years thatis from 2005 to 2009 a substantial warming was noticed withsignificant increase in the SST anomaly during this periodWhereas the maximum positive deviation of SST from theclimatological mean in the Red Sea and the Persian Gulf wasduring 2001 (+123 and+155 resp) in theGulf ofAden it wasin 1998 (+18) and in the Gulf of Oman in 2000 (+115) The

maximum negative deviation of SST from the climatologicalmean (ie maximum cooling) in the Persian Gulf and theGulf of Oman was in 1991 (minus14 and minus28 resp) whereasin the Red Sea Gulf of Aden Gulf of Kutch and Gulf ofKhambhat it was in 1992 (minus21 minus132 minus092 and minus141 resp)

During the southwest monsoon season (SWM) (JunendashSeptember) (Figure 4(c)) a cooling trend was observed inthe eastern gulfs of the Arabian Sea whereas in the westerngulfs a warming trend was found in the last 25 years withthe maximum increase of SST anomaly in the Red Sea(077decade) A similar pattern of SST anomaly was ob-served in the eastern gulfs ofArabian Sea on one hand and thewestern gulfs of Arabian Sea and the Red Sea on the otherhand However a careful examination revealed that in the last6 years (2003ndash2009) a substantial warming has been takingplace in both the eastern and western gulfs of the Arabian Seaduring the SWM season In the eastern and western gulfs ofArabian Sea and theRed Sea the SST anomaly increased from1985 to 1987-1988 followed by a phase of decreasing anomalywhich continued until 1990-1991 During the extended ElNino period of 1991ndash1995 a sharp rise in SST anomaly wasobserved in the eastern gulfs of the Arabian Sea after whichSST decreased till 2003 On the other hand in the westerngulfs of the Arabian Sea and the Red Sea the SST anomalyincreased substantially from 1991 till 1998 (with maximumpositive anomaly in 1998) However similar to the easterngulfs the SST anomalies again decreased from 1998 to 2003But from 2003 onwards a sharp rise of SST was observedtill 2009 in both the eastern gulfs and the western gulfs ofthe Arabian Sea and the Red sea with the maximum positivedeviation of SST anomaly in the year 2007 The Persian Gulfshowed positive SST anomalies in all the years from 1993 to2009 Even in the Red Sea from 1993 onwards the anomalieshave been positive except for the years 2000 and 2004 Theyears with strong positive SST anomaly (more than +10)during SWM season were 1995 1997 1998 and 2002 in theGulf of Aden 1995 1997 1998 2001 2007 and 2009 in the RedSea 1998 2002 and 2006 in the PersianGulf 1987 and 1993 inthe Gulf of Kutch and 1987 in the Gulf of Khambhat None ofthe years showed strong positive SST anomalies (more than+10) in the Gulf of Oman On the other hand the years withstrong negative SST anomaly (more than minus10) during SWMseason were 1985 1991 and 1994 in the Gulf of Aden 19851989 1990 and 1991 in the Red Sea 1991 in the Persian Gulf1989 1991 and 2003 in the Gulf of Oman 2001 and 2003 inthe Gulf of Kutch and the Gulf of Khambhat

During the fall intermonsoon (FIM) (October-November) an increasing trend of the normalized anomaliesfor the eastern and the western gulfs of the Arabian Sea andthe Red sea (Figure 4(d)) was observed The Red Sea andtheGulf of Kutch had amuch sharper increase in positive SSTanomalies (068decade and 066decade resp) than the restof the gulfs For both the eastern gulfs of the Arabian Seaa similar interannual variability pattern was observed In theGulf of Kutch and Gulf of Khambhat the SST anomalyincreased from 1985-1986 to 1989-90 followed by a substantialcooling which continued until 1994 (withmaximumnegativeanomaly in 1994) From 1994 to 2000 a warming phase wasfollowed by a cooling phase which continued up to the year

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geology Advances in

International Journal of Oceanography 11

2004 in the two eastern gulfs However in the last 4 yearsthat is from 2004 till 2008 the SST anomaly again increasedwith 2006 showing a high SST anomaly Overall in the Gulfof Kutch and Gulf of Khambhat a sharp rise of normalizedanomalies (warming) was found from 1994 onwards thoughthe rise was more pronounced in the Gulf of Kutch in whichfrom 1997 onwards (except for 2004) none of the yearsshowed negative departure from the climatological meanduring this season On the other hand in the western gulfsof the Arabian Sea and the Red Sea even though the patternof interannual variability during the FIM season was similara significant difference in the magnitude of variability wasnoticed especially in the Persian Gulf and the Red Seaowing to their enclosed locations In the Persian Gulf Gulfof Oman Red sea and Gulf of Aden the normalized SSTanomalies decreased from 1985 to 1991 (cooling) and there-after increased (warming) remarkably until 1998-1999 Even-tually from 1998-1999 to 2003-2004 the SST anomalies againdecreased significantly However similar to the eastern gulfsof the Arabian Sea the western gulfs and the Red Sea alsoexhibited warming from 2003-2004 to 2009 During theFIM in the Persian Gulf and the Gulf of Oman apart from1991 1996 also showed intense cooling with negative SSTanomaly reaching up to minus167

The influence of El Nino and La Nina on the interannualSST pattern during different seasons was observed Howevernot all the warming and cooling events had similar effect onthe SST anomaly Besides the geographical location of theparticular gulf also played a crucial role in determining theimpact of the ENSO

323 Coefficient of Variation of Annual and Seasonal SST ofthe Eastern and Western Gulfs of Arabian Sea and Red Seafrom 1985 to 2009 The coefficient of variation (CV) gives themagnitude of the interannual variability CV values of theannual and seasonal SST of the eastern and the western gulfsof the Arabian Sea and the Red Sea showed large variationamongst these water bodies as seen in Table 1

The largest variation in annual SST was found in thePersian Gulf (mean CV of 1802) followed by the Gulf ofOman (mean CV of 111) whereas Gulf of Aden was leastvariable (mean CV of 637) The interannual variability inseasonal mean SST was highest in the Persian Gulf in all theseasons except for the SWM season During SWM seasonthe maximum variability was observed to be in the Gulf ofKutch (mean CV of 1007) followed by Gulf of Khambhat(mean CV of 49) Gulf of Aden and Gulf of Oman wereleast variable during the NEM and SWM seasons whereasGulf of Khambhat was least variable during SIM and FIMseasons

33 Comparison of Normalised SST Anomaly of the Easternand Western Gulfs of Arabian Sea and Red Sea with Multi-variate ENSO Index and Role of Indian Ocean Dipole TheEl NinoSouthern Oscillation (ENSO) is a phenomenon thatintegrates both atmospheric and oceanic parameters and ismeasured by various indices like the Southern OscillationIndex (SOI) Multivariate ENSO Index (MEI) Nino 34 and

Table 1 Coefficient of variation for annual and seasonal SST

GulfSea Annual NEM SIM SWM FIMPersian Gulf 1802 788 1177 268 777Gulf of Oman 111 385 837 193 461Red Sea 802 356 465 276 383Gulf of Aden 637 220 468 263 384Gulf of Kutch 935 506 363 1007 314Gulf of Khambhat 65 4 213 490 283

so forth [48ndash51] El Nino and LaNina result from interactionbetween the ocean and the atmosphere in the tropical PacificThe warm El Nino to cold La Nina conditions oscillate on anaverage of every three to five years Of all these indicesMEI arepresentative of SST sea surface pressure zonal and merid-ional components of the surface wind air temperature andcloudiness of the sky gives more structured informationabout ENSO phenomena and its correlation with surfacetemperature [52] Hence in this study MEI was used to findthe relationship between ENSO events and the change in theSST pattern in the gulfs of the Arabian Sea as seen in Figure 5

Besides ENSO the Indian Ocean Dipole (IOD) is alsoknown to be affecting the interannual SST anomalies Onephase of the IOD (positive IOD or PIOD) causes a cooling ofSST in the eastern tropical Indian Ocean while the westerntropical Indian Ocean (western Arabian Sea) tends to experi-ence a warming of sea surface temperatures The other phase(negative IOD or NIOD) in contrast involves high SST in theeastern Indian Ocean and low in the west [49 53 54] Somedipole events occur without ENSO events and some ENSOevents do not accompany the dipole events When an ENSOevent occurs the dipole tends to be positive during El Ninoand negative during La Nina However the amplitude of thedipole varies greatly from year to year 1991 1994 1997-1998are reported to be the positive IOD years whereas 1992 1996and 1998 are reported to be negative IOD years [55]

The major El Nino events of 1986-1987 1991-1992 1997-1998 2002-2003 2006-2007 and 2009-2010 and the La Ninaevents of 1988-1989 1998-1999 2000-2001 and 2007-2008 areevident from the peaks and troughs of the MEI values withpositive MEI values indicating a warming event (El Nino)and the negative MEI value indicating a cooling event (LaNina) The influence of the ENSO on SST of the Gulfs ofthe Arabian Sea can be clearly seen However one to oneconnection was not found Besides not all the El Nino orLa Nina events had similar impact in the eastern and thewestern gulfs of the Arabian Sea For example the El Ninoof 1991-1992 and 1994-1995 did not influence the eastern gulfsof theArabian Sea as comparedwith the one of 1997-1998Theyear 1997-1998 was also a positive IOD year Hence theextent of warming especially in the western gulfs of theArabian Sea and the Red Sea was high Besides in 1992 ahigh negative anomaly in the western gulfs and the Red Seawas observed owing to the influence of the negative IODMoreover the impact of an IODwas seenmore in the westerndomains of the Arabian Sea During the extended El Ninoof 1991ndash1995 the normalized positive SST anomaly increasedremarkably in all the gulfs except the Gulf of Kutch and

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geological ResearchJournal of

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Geology Advances in

12 International Journal of Oceanography

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiPersian Gulf

(a)

minus1minus2minus3

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Oman

(b)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

YearMeiGulf of Aden

minus1minus2minus3

(c)

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Red SeaMei

minus1minus2minus3

(d)

Mei

0123

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Nor

mal

ized

anom

aly

Year

Gulf of Kutch

minus1minus2minus3

(e)

Mei

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009N

orm

aliz

ed an

omal

y

Year

Gulf of Khambhat

0123

minus1minus2minus3

(f)

Figure 5 Comparison of normalised SST anomaly of (a) Persian Gulf (b) Gulf of Oman (c) Gulf of Aden (d) Red Sea (e) Gulf of Kutchand (f) Gulf of Khambhat from 1985 to 2009 along with Multivariate ENSO Index (MEI)

Gulf of Khambhat Similarly the stronger El Nino of 1997-1998 had a major impact on all gulfs except for the Gulf ofKutch However a delayed effect was observed in the PersianGulf Gulf of Oman and Red Sea with peaks of normalisedanomalies in 1998-1999 The La Nina of 1988-1989 resulted incooling of Gulf of Oman Red Sea and Gulf of Aden but hadno influence in the Gulfs of Kutch and Khambhat whereasthe La Nina of 2008 affected all the gulfs except for the RedSea

4 Discussion

Time series studies of the oceanographic parameters areuseful for understanding seasonal interannual and decadalimpact of climate change Numerous investigations have beenconducted in the Arabian Sea basin to study the effect ofglobal warming Rupa Kumar et al [17] reported that from1904 to 1994 the Arabian Sea has warmed by 05∘C Recentstudies have also confirmed about the warming of the

Arabian Sea by 016∘Cdecade from 1971 to 2002 [18] and010∘Cdecade from 1982 to 2006 [56] Kailasam and Rao[20] using GISS Surface Temperature observed that there hasbeen an increasing trend of SST with strong positive SSTanomalies (08∘C) during the period of 1981ndash2009 over theNorthern Indian Ocean

However as the gulfs of the Arabian Sea have uniqueoceanographic features and are quite distinct from the openocean it becomes essential to study them individually Thesegulfs are single watermasses and therefore studies conductedin few of the coastal areas cannot be generalized for the wholeof the gulfs In the present study a comparative analysis ofSST in different months and seasons was carried out for theeastern and western gulfs of the Arabian Sea and the Red Seafrom 1985 to 2009 to study the regional effect of the warmingof the Arabian Sea Annually the SST has increased signifi-cantly in all the western gulfs of the Arabian Sea and the Redsea with maximum increase of normalized SST anomaly inthe Red sea (064decade) and the PersianGulf (040decade)

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Geology Advances in

International Journal of Oceanography 13

However the increase was not significant for the eastern gulfsof the Arabian Sea (Gulf of Kutch and Gulf of Khambhat)

The analysis by Kumar et al [19] about the anthropogenicinduced global warming disrupting the decadal cycle of SSTof Arabian Sea after 1995 was also observed in the presentstudy in the eastern gulfs of the Arabian Sea (Gulf of Kutchand Gulf of Khambhat) where the annual SST increasedrapidly from 1995 onwards However in the western gulfs(Persian Gulf Gulf of Oman and Gulf of Aden) and the RedSea the disruption of the decadal cycle of SST resulting ina sharp rise of SST was observed from the year 1991-1992Therefore a remarkable time lag of (3 years) between theeastern and the western gulfs of the Arabian Sea and the Redsea was observed in the annual increase of SST There wassimilarity in the interannual variability pattern of SSTamongst the western gulfs and the Red sea on one hand andthe eastern gulfs on the other

Annually for western gulfs of the Arabian Sea that isthe Persian Gulf Gulf of Oman and Gulf of Aden coolingwas observed from 1985 to 1991 and thereafter from 1992 to2009 warming was foundWhereas in the eastern gulfs of theArabian Sea that is the Gulf of Kutch and Gulf of Khambhata significant cooling was observed from 1985 to 1994 andthereafter from 1995 to 2009 a sharp increase in normalizedanomaly was found In the three western gulfs of the ArabianSea (Persian Gulf Gulf of Oman and Gulf of Aden) themaximumnegative normalized SST anomalywas observed in1991 In the Red Sea the maximum negative normalized SSTanomaly was found in 1992 (negative IOD) On the otherhand in both the eastern gulfs of the Arabian Sea maximumnegative normalized SST anomaly was observed in 1994 Inthe western gulfs of Arabian Sea and the Red Sea 1997-1998 1999 2001 2002 2006 2007 and 2009 were the yearswith high positive normalized SST anomalies whereas in theeastern gulfs of the Arabian Sea the years 2002 2007 and2009 showed strong positive SST anomalies Most of theseyears are reported to be the El Nino years like 1997-98 20022006 and 2009 which affected the SST variability pattern

The seasonal SST analysis for the western gulfs of theArabian Sea and the Red Sea showed an increasing trend ofSST in all the four seasonsHowever in the eastern gulfs of theArabian Sea during the SWM season cooling was observedDuring the NEM and the SIM seasons similar interannualSST variability pattern was observed in the Persian Gulf Gulfof Oman and the Red Sea on one hand and Gulf of AdenGulf of Kutch and Gulf of Khambhat on the other During theSWM and FIM seasons similar interannual SST variabilitypattern was in the eastern gulfs of Arabian Sea on one handand the western gulfs of Arabian Sea and the Red Sea on theother

During the NEM season in the Persian Gulf Gulf ofOman and the Red Sea an alternate cycle of cooling andwarming phases was observed from 1986 to 1992 1992 to1999 1999 to 2005 and 2005 to 2009 whereas in the easterngulfs of the Arabian Sea and the Gulf of Aden the alternatecycle of cooling and warming phases was observed from1986 to 1990 1990 to 1995 (1997 in Gulf of Aden) 1995 to2001-2002 (2003 in Gulf of Aden) 2001-2002 to 2005 and

2005 to 2009 The Persian Gulf Gulf of Oman and the RedSea exhibited maximum cooling during 1992 owing to thenegative IOD During the NEM season the years 1987 1989and 2008 showed the influence of LaNina with high negativeSST anomalies in the western gulfs of the Arabian Sea and theRed Sea But in the eastern gulfs of the Arabian Sea only theinfluence of La Nina of 2008 was visible Similarly of all theEl Nino years 1991ndash1995 2002 and 2006 resulted in a higherpositive SST anomaly in the eastern and the western gulfs ofthe Arabian Sea and the Red sea

Similarly during the SIM season alternate warming andcooling phases were noticed in the eastern gulfs of the Ara-bian Sea and the Gulf of Aden from 1985 to 1991-1992 1991-1992 to 1998 1998 to 2004-2005 (2003 for Gulf of Aden) and2004-2005 to 2009 In the eastern gulfs of theArabian Sea themaximum positive SST anomaly during SIMwas in 2002 thatwas an El Nino year Amongst the rest of the western gulfsof the Arabian Sea and the Red Sea the alternate phases ofwarming and cooling were observed from 1985 to 1991-19921991-1992 to 2001 2001 to 2005 and 2005 to 2009 Themaximum negative deviation of SST from the climatologicalmean in the Red Sea Gulf of Aden Gulf of Kutch andGulf ofKhambhatwas in 1992 owing to the negative IODDuring theSIM the influence of El Nino of 1991ndash1995 1997-1998 2002and 2009 and La Nina of 1987 and 1989 could be seen on theSST anomalies of the eastern and the western gulfs and theRed Sea

In the SWM season the periods of warming and coolingincluded 1985 to 1987-1988 1987-1988 to 1990-1991 1991 to1995 (1998 for the western gulfs and the Red Sea) 1995 to2003 and 2003 to 2009 The Persian Gulf and the Red Seashowed positive SST anomalies in all the years from 1993 to2009 The years with strong positive SST anomaly were 19951997 1998 and 2002 in theGulf ofAden 1995 1997 1998 20012007 and 2009 in the Red Sea 1998 2002 and 2006 in thePersianGulf and 1987 and 1993 in the Gulf of Kutch and 1987in the Gulf of Khambhat of whichmost of the years like 19951997 1998 2002 2006 and 2009were the ElNino years How-ever the influence of La Nina was not seen during SWMseasonThe years with negative SST anomalies included 19851991 and 1994 in the Gulf of Aden 1985 1989 1990 and 1991in the Red Sea 1991 in the Persian Gulf 1989 1991 and 2003in the Gulf of Oman 2001 and 2003 in the Gulf of Kutch andthe Gulf of Khambhat

During the FIM season an increasing trend of thenormalized anomalies for the eastern and the western gulfs ofthe Arabian Sea and the Red sea was observed In the easterngulfs the alternate phases of increasing and decreasing SSTanomaly included 1985-1986 to 1989-1990 1989-1990 to 19941994 to 2000 2000 to 2004 and 2004 to 2009 In the westerngulfs of the Arabian Sea and the Red Sea the phases ofwarming and cooling included 1985 to 1991 1991 to 1998-19991998-99 to 2003-2004 and 2003-2004 to 2009The years withhigh negative SST anomalies during the FIMwere 1986 19881991 and 1994 in the Gulf of Aden whereas in the Red Seathese were 1985 1988 and 1991 Of these 1985 and 1988 werethe La Nina yearsThe years with strong positive SST anoma-lies during the FIM were 1986 1998 2001 2004 and 2006

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MineralogyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

14 International Journal of Oceanography

in the Persian Gulf 1999 and 2006 in Gulf of Oman 1998 and2002 inGulf of Aden and 1998 2001 and 2002 in the Red SeaOf these 1986 1988 2002 and 2006 were the El Nino years

The contrasting features between the eastern and westerngulfs of the Arabian Sea could be attributed to their differencein oceanographic features current systems and also anthro-pogenic impact Being enclosed in semiarid surroundings inthe northern edges of the Indian subtropical zone thewesterngulfs of the Arabian Sea come under the direct influence ofmultiple atmospheric pressure systems like the impact of theSiberian high pressure system the El Nino Southern Oscil-lation the North Atlantic Oscillation and the IOD [57] Theinfluence of the ENSO and the IOD affecting the interannualvariability of SSTwas found However one to one connectionwas not found Besides not all the El Nino or La Nina eventshad similar impact in the eastern and the western gulfs of theArabian Sea The year 1997-1998 was an ENSO dipole yearHence the extent of warming especially in the western gulfsof the Arabian Sea and the Red Sea was high Besides in 1992a high negative anomaly in the western gulfs and the Red Seawas observed owing to the strong influence of the negativeIOD During the extended El Nino of 1991ndash1995 thenormalized positive SST anomaly increased drastically in allthe gulfs except the Gulf of Kutch and Gulf of KhambhatSimilarly the stronger El Nino of 1997-1998 had a majorimpact on all gulfs except for the Gulf of Kutch The atmo-spheric temperature over the Persian Gulf including the Gulfof Oman has been reported to be increasing rapidly and isprojected to further increase up to 4∘C by the end of thecentury [58] There are reports of the weakening of theSiberian high pressure system resulting in a decline in thezonal component of wind and hence an increase in surfacetemperature [59] Besides the regional orography of thesurrounding land masses which includes deserts and moun-tains also affects the physical oceanographic processes of thewestern gulfs of the Arabian Sea However the most signif-icant contributor for the sharp rise of SST in the westerngulfs of the Arabian Sea that has resulted in disruption of thedecadal SST cyclemuch ahead of that of theArabian Sea basinand the eastern Gulf is the increasing anthropogenic inducedwarming There has been tremendous increase in humanactivities in the countries surrounding the western gulfs ofthe Arabian Sea which have contributed to the higher rate ofwarming along these western gulfs of the Arabian Sea ascompared to the Arabian Sea basin and its eastern gulfs

5 Conclusion

Sea surface Temperature (SST) is one of the key oceano-graphic parameters exerting an influential role inmany of themeteorological and oceanographic processes From 1985 to2009 the SST of the eastern and western gulfs of the ArabianSea and the Red sea showed a clear cut signal of warmingThe rate of increase of SST was highest in the Persian Gulffollowed by theRed Sea From 1991-1992 onwards thewesterngulfs of the Arabian Sea and the Red sea exhibited a sharpincrease in SST whereas in the eastern gulfs of the ArabianSea the warming was more pronounced from 1995 onwards

Seasonal differences were also found with respect to increas-ing temperature Interannual variability pattern was foundto be similar in the annual and seasonal SST amongst thewestern gulfs and the Red Sea Similarity in SST variabilitywas also found in the two of the eastern gulfs of the ArabianSea Red Sea was found to be warming significantly across allthe seasons and months The largest variation in annual SSTwas found in the Persian Gulf (CV of 1802) The inter-annual variability in seasonal mean SST was highest in thePersian Gulf in all the seasons except for the SWM seasonDuring SWM season the maximum variability was observedin the Gulf of Kutch (CV of 1007) followed by Gulfof Khambhat (CV of 49) The influence of ENSO andIOD on the SST variability pattern was also found Theimpact of rising temperature on other physical and biologicalparameters of the gulfs of the Arabian Sea and the Red Seaneeds to be scrutinized further

The difference in the oceanographic features of theeastern and western gulfs of the Arabian Sea and the Red Seafrom the open oceans makes themunique ecosystemHencecaution is needed to analyze them individually and not togeneralize the findings of the entire basin upon them

Acknowledgments

The authors are thankful to NASArsquoS Jet Propulsion Labora-toryrsquos Physical Oceanographic Centre and Climate Diagnos-tic Centre for providing the data

References

[1] S Solomon D Qin M Manning et al Eds Climate Change2007The Physical Science Basis Contribution ofWorking GroupI to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change Cambridge University Press CambridgeUK 2007

[2] A J Richardson and D S Schoeman ldquoClimate impact onplankton ecosystems in the Northeast Atlanticrdquo Science vol305 no 5690 pp 1609ndash1612 2004

[3] M J Behrenfeld R T OrsquoMalley D A Siegel et al ldquoClimate-driven trends in contemporary ocean productivityrdquoNature vol444 no 7120 pp 752ndash755 2006

[4] R Ji C S Davis C Chen D W Townsend D G Mountainand R C Beardsley ldquoInfluence of ocean freshening on shelfphytoplankton dynamicsrdquo Geophysical Research Letters vol 34no 24 Article ID L24607 2007

[5] B S Halpern S Walbridge K A Selkoe et al ldquoA global mapof human impact on marine ecosystemsrdquo Science vol 319 no5865 pp 948ndash952 2008

[6] J E Hansen and S Lebedeff ldquoGlobal trends ofmeasured surfaceair temperaturerdquo Journal of Geophysical Research Solid Earthvol 92 no B1 pp 345ndash355 1987

[7] J Hansen ldquoPublic understanding of global climate changerdquo inCarl Saganrsquos Universe Y Terzian and E Bilson Eds pp 247ndash253 Cambridge University Press New York NY USA 1997

[8] C K Folland N A Rayner S J Brown et al ldquoGlobal tem-perature change and its uncertainties since 1861rdquo GeophysicalResearch Letters vol 28 no 3 pp 2621ndash2624 2001

[9] N A Rayner D E Parker E B Horton et al ldquoGlobal analysesof sea surface temperature sea ice and night marine air

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MineralogyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

International Journal of Oceanography 15

temperature since the late nineteenth centuryrdquo Journal ofGeophysical Research Atmospheres vol 108 no D14 p 44072003

[10] S C Doney ldquoOceanography plankton in a warmer worldrdquoNature vol 444 no 7120 pp 695ndash696 2006

[11] F Montaigne ldquoThe global fish crisisrdquo National Geographic vol211 no 4 pp 32ndash99 2007

[12] P D Jones and T M L Wigley ldquoEstimation of global temper-ature trends whatrsquos important and what isnrsquotrdquo Climate Changevol 100 pp 59ndash69 2007

[13] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[14] S A Henson J L Sarmiento J P Dunne et al ldquoIs globalwarming already changing ocean productivityrdquo BiogeosciencesDiscussions vol 6 no 6 pp 10311ndash10354 2009

[15] J Hansen R Ruedy M Sato and K Lo ldquoGlobal surfacetemperature changerdquo Reviews of Geophysics vol 48 no 4Article ID RG4004 2010

[16] O P Singh ldquoRecent trends in summer temperatures over theNorth Indian Oceanrdquo Indian Journal of Marine Sciences vol 29no 1 pp 7ndash11 2000

[17] R Rupa Kumar K Krishna Kumar R G Ashrit S K Patward-han and G B Pant ldquoClimate change in India observationsand model projectionsrdquo in Climate Change and India IssuesConcerns and Opportunities P R Shukla S K Sharma and PVenkata Ramana Eds TataMcGraw-Hill Publishing CompanyLimited New Delhi India 2002

[18] D R Kothawale A A Munot and H P Borgaonkar ldquoTem-perature variability over the Indian Ocean and its relationshipwith Indian summermonsoon rainfallrdquoTheoretical and AppliedClimatology vol 92 no 1-2 pp 31ndash45 2008

[19] S P Kumar R P Roshin J Narvekar P K D Kumar and EVivekanandan ldquoResponse of the Arabian Sea to global warmingand associated regional climate shiftrdquo Marine EnvironmentalResearch vol 68 no 5 pp 217ndash222 2009

[20] M K Kailasam and R S Rao ldquoImpact of global warmingon tropical cyclones and monsoonsrdquo in Global Warming SAHarris Ed 2010 httpwwwintechopencombooksglobal-warmingimpact-of-global-warming-on-indian-monsoons

[21] C R C Sheppard and A L S Sheppard ldquoCorals and coralcommunities of Arabiardquo Fauna of Saudi Arabia vol 12 pp 3ndash170 1991

[22] C Sheppard A Price and C Roberts Marine Ecology of theArabian Region Patterns and Processes in Extreme TropicalEnvironments Academic Press London UK 1992

[23] R F G Ormond and S A Banaimoon ldquoEcology of intertidalmacroalgal assemblages on the Hadramout coast of southernYemen an area of seasonal upwellingrdquoMarine Ecology ProgressSeries vol 105 no 1-2 pp 105ndash120 1994

[24] M Goren and M Dor An Updated Checklist of the Fishes ofthe Red Sea CLOFRES 11 Academy of Sciences and HumanitiesJerusalem Israel 1994

[25] S Al-Muzaini and P G Jacob ldquoMarine plants of the ArabianGulfrdquo Environment International vol 22 no 3 pp 369ndash3761996

[26] J M Kemp ldquoZoogeography of coral reef fishes of the Gulf ofAdenrdquo Fauna of Arabia vol 18 pp 293ndash321 2000

[27] B Riegl ldquoClimate change and coral reefs different effects in twohigh-latitude areas (Arabian Gulf South Africa)rdquo Coral Reefsvol 22 no 4 pp 433ndash446 2003

[28] S L Coles Coral Species Diversity and Environmental Factorsin the Arabian Gulf and the Gulf of Oman A Comparisonto the Indo-Pacific Region vol 507 of Atoll Research BulletinNational Museum of Natural History Smithsonian InstitutionWashington DC USA 2003

[29] A M Dixit P Kumar L Kumar K D Pathak and M I PatelEconomic Valuation of Coral Reef Systems in Gulf of KachchhFinal Report World Bank Aided Integrated Coastal Zone Man-agement (ICZM) Project Gujarat Ecology Commission 2010

[30] PERSGAGEFThe Red Sea and Gulf of Aden Regional Networkof Marine Protected Areas Regional Master Plan PERSGATechnical Series no 1 PERSGA Jeddah Saudi Arabia 2002

[31] C Sheppard M Al-Husiani F Al-Jamali et al ldquoThe Gulf ayoung sea in declinerdquo Marine Pollution Bulletin vol 60 no 1pp 13ndash38 2010

[32] W Gladstone B Curley and M R Shokri ldquoEnvironmentalimpacts of tourism in the Gulf and the Red Seardquo MarinePollution Bulletin 2012

[33] W Hamza and M Munawar ldquoProtecting and managing theArabian Gulf past present and futurerdquo Aquatic EcosystemHealth and Management vol 12 no 4 pp 429ndash439 2009

[34] C Sheppard ldquoThe main issues affecting coasts of the Indianand Western Pacific oceans a meta-analysis from Seas at theMillenniumrdquoMarine Pollution Bulletin vol 42 no 12 pp 1199ndash1207 2001

[35] A N Al-Ghadban and A R G Price ldquoDredging and infillingrdquoinTheGulf Ecosystem Health and Sustainability N Y Khan MMunawar and A Price Eds pp 207ndash218 Bakhuys LeidenTheNetherlands 2002

[36] S-Y Chao T W Kao and K R Al-Hajri ldquoA numericalinvestigation of circulation in the Arabian Gulfrdquo Journal ofGeophysical Research vol 97 no 7 pp 11219ndash11236 1992

[37] R M Reynolds ldquoPhysical oceanography of the Gulf Strait ofHormuz and the Gulf of Omanmdashresults from the Mt MitchellexpeditionrdquoMarine Pollution Bulletin vol 27 pp 35ndash59 1993

[38] M A Al Saafani and S S C Shenoi ldquoWater masses in the Gulfof Adenrdquo Journal of Oceanography vol 63 no 1 pp 1ndash14 2007

[39] V S Kumar and K A Kumar ldquoWaves and currents in tide-dominated location offDahej Gulf of Khambhat IndiardquoMarineGeodesy vol 33 no 2-3 pp 218ndash231 2010

[40] E Kalnay M Kanamitsu R Kistler et al ldquoThe NCEPNCAR40-year reanalysis projectrdquo Bulletin of the AmericanMeteorolog-ical Society vol 77 no 3 pp 437ndash471 1996

[41] M Rouault B Pohl and P Penven ldquoCoastal oceanic climatechange and variability from 1982 to 2009 around South AfricardquoAfrican Journal of Marine Science vol 32 no 2 pp 237ndash2462010

[42] P C McClain ldquoOverview of the satellite data applications inthe climate and earth sciences laboratory of NOAArsquoS NationalEnvironmental Satellite data and information servicesrdquo in Pro-ceeding of the US-India Symposium-Cum Workshop on RemoteSensing Fundamentals and Applications pp 1ndash18 1985

[43] S Krishnaswami and R Nair ldquoJGOFS (India)mdashintroductionrdquoCurrent Science vol 71 pp 831ndash833 1996

[44] J Fang S Piao Z Tang C Peng and W Ji ldquoInterannual vari-ability in net primary production and precipitationrdquo Sciencevol 293 no 5536 p 1723 2001

[45] J G Colborn Thermal Structure of the Indian Ocean IIOEMonograph no 2 An East West Press 1975

[46] R R Rao R L Molinari and J F Festa ldquoEvolution of theclimatological near-surface thermal structure of the tropical

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MineralogyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

16 International Journal of Oceanography

Indian Ocean 1 Description of mean monthly mixed layerdepth and sea surface temperature surface current and surfacemeteorological fieldsrdquo Journal of Geophysical Research vol 94no 8 pp 10801ndash10815 1989

[47] T G Prasad and M Ikeda ldquoA numerical study of the seasonalvariability of Arabian Sea high-salinity waterrdquo Journal of Geo-physical Research C vol 107 no 11 pp 18-1ndash18-12 2002

[48] G T Walker ldquoCorrelation in seasonal variations of weatherrdquoMemoirs of the India Meteorological Department vol 24 pp333ndash345 1924

[49] N H Saji B N Goswami P N Vinayachandran and TYamagata ldquoA dipolemode in the tropical Indian oceanrdquoNaturevol 401 no 6751 pp 360ndash363 1999

[50] D W J Thompson J M Wallace P D Jones and J J KennedyldquoIdentifying signatures of natural climate variability in timeseries of global-mean surface temperature methodology andinsightsrdquo Journal of Climate vol 22 pp 6120ndash6141 2009

[51] G Foster J DAnnan PD Jones et al ldquoComment on ldquoinfluenceof the Southern Oscillation on tropospheric temperaturerdquo byJ D McLean C R de Freitas and R M Carterrdquo Journal ofGeophysical Research Atmospheres vol 115 no D9 Article IDD09110 2010

[52] K Wolter and M S Timlin ldquoMonitoring ENSO in COADSwith a seasonally adjusted principal component indexrdquo inProceedings of the 17th Climate Diagnostics Workshop pp52ndash57 NOAANMCCAC NSSL Oklahoma ClimatologicalSurvey CIMMS and the School of Meteorology University ofOklahoma Norman Okla USA 1993

[53] P J Webster A M Moore J P Loschnigg and R R LebenldquoCoupled ocean-atmosphere dynamics in the Indian Oceanduring 1997-98rdquo Nature vol 401 no 6751 pp 356ndash360 1999

[54] T Yamagata S K Behera S A Rao and N H Saji ldquoCommentson lsquodipoles temperature gradients and tropical climate anoma-liesrsquordquo Bulletin of the AmericanMeteorological Society vol 84 no10 pp 1418ndash1422 2003

[55] M Nagura and M Konda ldquoThe seasonal development of anSST anomaly in the IndianOcean and its relationship to ENSOrdquoJournal of Climate vol 20 no 1 pp 38ndash52 2007

[56] I M Belkin ldquoRapid warming of large marine ecosystemsrdquoProgress in Oceanography vol 81 no 1ndash4 pp 207ndash213 2009

[57] T Shinoda H H Hendon and M A Alexander ldquoSurface andsubsurface dipole variability in the IndianOcean and its relationwith ENSOrdquoDeep-Sea Research Part I vol 51 no 5 pp 619ndash6352004

[58] G A Meehl T F Stocker and W D Collins ldquoGlobal climateprojectionsrdquo inClimate Change 2007The Physical Science BasisContribution of Working Group I to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change SSolomonDQinMManning et al Eds pp 80ndash87 CambridgeUniversity Press New York NY USA 2007

[59] S A Piontkovski M Al-Gheilani P B Jupp R A Al-Azriand A K Al-Hashmi ldquoInterannual changes in the sea of omanecosystemrdquoThe Open Marine Biology Journal vol 6 pp 38ndash522012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MineralogyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

EarthquakesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MineralogyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geological ResearchJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Geology Advances in