cyclone phalin, helen, haiyan and basic theory on clouds (1)

7/23/2019 Cyclone Phalin, Helen, Haiyan and Basic Theory on Clouds (1)

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Clouds , Ocean Currents , Cyclone Phalin, Helen and Typhoon Haiyan

1. Prologue

2. Dawn & Twilight

3. Clouds & Precipitation

4. Relative Humidit

!. Tpes o" Precipitation & #orms o" Precipitation

$. Classi"ication o" clouds

%. Cloud urst' Cloud (eeding

). *cean Currents +,arm and Cold-.

. Cclone Phalin +/nd e0cellent wor ndian overnment-' Cclone Helen +*n the

wa-

15. Tphoon Haian

Note An article for GS-1 only. (Not for students with Geography as optional). As very few

articles written on geography subect so writing this one.

Dawn and Twilight

The di""used light that occurs e"ore sunrise and a"ter sunset. 6ight is scattered the molecules

o" the atmospheric gases & re"lected dust and moisture so that7 the atmosphere is illuminated.

(uch e""ects ma e enhanced the presence o" pollution & other suspended particles7 such as

those "rom volcanic eruption or "orest "ires.

The duration o" Dawn & Twilight is a function of latitude because the angle of the sun!s path

above the hori"on7 determines the thicness o" atmosphere7 through which the sun8s ras must

pass.

6ower (un8s angles+higher latitudes- produce longer dawn & the twilight period

#or e.g at 9:uator +each dawn & twilight- ;; 35


2/17

The poles e0perience aout % wees o" Dawn & % wees o" Twilight7 leaving onl aout 2.!

months o" near darness during the $ months when the sun is completel elow the Hori=on

>ust an e0ample ? (tudents interested in tennis will certainl rememer this#oger $ederer vs

Nadal match at ,imeldon+6ondon- "inals 255)7 went wa past eond .35pm (T+ritish

standard time- and still there was light on the ground. That was due to the 2.! hours dawn and

twilight

Clouds

Cloud ? The visible %anifestation of condensationon a large scale in nature is re"erred to as

cloud. +,ill e0plain condensation later @ no need to worr-.

Clouds "orm when air happens to cool to dew point & the vapor condenses into water droplets or

ice


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Condensation


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Relative humidityis the ratio o" the current asolute humidit to the highest possile asolute

humidit +which depends on the current air temperature-. / reading o" 155 percent relative

humidit means that the air is totall saturated with water vapor and cannot hold an more7creating the possiilit o" rain.

Precipitation < Precipitation is an "orm o" moisture which "alls to the earth. This includes rain7snow7 hail and sleet.

Precipitation occurs when water vapor cools. ,hen the air reaches saturation point +also nownas condensation point and dew point- the water vapor condenses and "orms tin droplets o"

water. These tin droplets o" water "rom clouds.

Comple0 "orces cause the water droplets to "all as rain"all.

/ll rain is the same. t happens as the result o" warm7 moist air eing cooled7 leading to

condensation and in turn rain.

The wa the air is upli"ted to mae clouds is re"erred to as tpe o" precipitation + +hoda sa toh lift

,arade-. 3 Baor tpes o" precipitation

i- Convectional

ii- #rontal

iii- *ro


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!tep "#

The sun heats the ground and warm air rises.

!tep $

/s the air rises it cools and water vapor condenses to "orm clouds.

!tep %#

,hen the condensation point is reached large cumulonimus clouds +e0plained later- are "ormed.

!tep

Heav rain storms occur. These usuall include thunder and lightning due to the electrical charge

created unstale conditions.

Convective precipitation is showerE with large rain drops coming "ast ut onl "or a shortduration. This precipitation is restricted in terms o" latitude7 season & time o" da.

'rontal Precipitation? This taes place especiall in middle latitudes +e0ample FG-7 when two

contrasting air masses meet7 the warm air rises. This occurs when a warm air mass and a cold airmass meet. / warm "ront is discovered when warm air advances and rises over the cold7 which is

heavier and denser. /s this warm air rises it also cools causing condensation taes places. " this

condensation continues there will e a growth in warm droplets which "all as rain when heav

enough.

!tep "#

/n area o" warm air meets and area o" cold air.

!tep $#

The warm air is "orced over the cold air


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!tep %#

,here the air meets the warm air is cooled and water vapour condenses.

!tep

Clouds "orm and precipitation occurs

Orographic PrecipitationRelie* Rain*all

This precipitation can occur at an latitude7 an season7 an time o" the da7 i" there is a arrier

& %oist air(air that is a %iture of dry air and any a%ount of water vapor)is "orced to move up.

t is more liel to e general & prolonged ecause there is relativel stead upslope "low o" air.

!tep "#

,arm wet air is "orced to rise over high land.

!tep $#

/s the air rises it cools and condenses. Clouds "orm and precipitation occurs.

!tep %#

The drier air descends and warms.

!tep

/n moisture in the air +e.g. cloud- evaporates.

Classi"ication o" clouds + lue howard in 1)53-

2 Dimensions o" cloud a- shape -height

!hape

Howard used 3 latin words "or designating 3 standard shapes

a- Cirrus +6oc o" curl hair-


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- (tratus +/ 6aer sheet'sheet'ceiling-

c- Cumulus +a heap or a pile-

Howard also used the wordimuswhich means a rain


8/17

a- /lto ? cumulus ; these are wool ump clouds arranged in laers & appearing lie

waves in the lue s. ote ; these clouds normall indicate "ine weather.

- /lto ? (tratus +/lt


9/17

1- Rain +Diameter ranging "rom 5.! mm to $ mm +mm ; milli metre--. This is the most

common "orm caused due to

a- ,hen dew point temperature is more than "ree=ing

- Belting o" ce


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Ocean Currents(.n a nutshell only *or -!.)

/n ocean current is an more or less permanent or continuous7 directed movement o" ocean

water that "lows in one o" the 9arthAs oceans. The currents are generated "rom the "orces actingupon the water lie the earthAs rotation7 the wind7 the temperature and salinit di""erences and the

gravitation o" the moon.

*cean currents can "low "or thousands o" ilometers. The are ver important in determining the

climates o" the continents7 especiall those regions ordering on the ocean.

enerall the term ocean current is used to horizontal movement in the upper most 100 metre

of water called surface layer. The ocean current are classi"ied as warm and cold on a relative

asis with respect to the surrounding waters. The so called warm & cold currents usuall e0hiit

temperatures that di""er onl a "ew degrees "rom those o" the surrounding waters.

n general the currents moving "rom lower to the higher latitudes are warm currents & the ones

which are moving "rom the higher to lower latitudes are called cold current. The current near thee:uator are generall classi"ied as warm current.

*n the asis o" volume o" water7 speed & dimensions the ocean currents are classi"ied as

a- Dri*ts+Re"ers to slow motion o" sur"ace laer7 with no clear oundaries. The movemento" water is erratic in terms o" direction. !peed may e etween "/$& 0mday)

- Currents+re"ers to sur"ace movement7 which is more rapidl & more de"ined than the

dri"t. !peed is /1 0mhour-

c- !treams+re"ers to sur"ace motion7 which is much more well de"ined7 its oundaries are

more clearl identi"iale.-

!ome important e2amples o* ocean current

,arm Currents+lower to higher latitudes' /scending order-

1- orth 9:uatorial current

2- (outh 9:uatorial current

3- 9:uatorial counter current

4- orth Paci"ic current

!- Guru (hio or >apan current

$- 9ast /ustralia current

%- ra=il Current


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)- ul" (tream

- orth /tlantic Dri"t

15- Bo=ami:ue Current

Cold Currents +Higher to lower latitudes' Descending order-

1- 6arador Current2- (outh ,est & orth 9ast Bonsoon Dri"t

3- engula Current

4- #alland Current

!- *a (hio'Gamchata Current

$- ,est /ustralian Current

,arm and cold Currents Diagram+Please rememer 6atitudes high to low+Descending ; cold-'low to high+/scending ; warm--

Cclone Phalin 2513

!evere Cyclonic !torm Phailin+ meaning KsapphireK- was a power"ul tropical cclone that

caused sustantial damage(Note - 01 people dead-7 in /ndhra Pradesh and *rissa7 ndia. t was


12/17

the most intense cclone that crossed ndian coast a"ter the 1 *disha cclone +ote< more

than 157555 people died during 1 cclone-

*ver 2557555 hectares o" agricultural land and 2557555 houses have een destroed7 as per the

state government. Power transmission was also crippled in the district as 45 transmission towers

were eradicated the ccloneAs "ur. alasore and Baurhan districts were severel a""ected heav "loods7 and rescue operations are going on. n alasore alone7 3557555 people are stucecause o" the "looding.

n /ndhra Pradesh the damage was less7 ut still considerale. Coconut plantations across 37255hectares in the (riaulum district have een damaged and power suppl a""ected. However7

power suppl is eing restored shortl and roads have een cleared "or transportation.

Areas A**ected y Cyclone Phailin

alasore7 hadra7 Baurhan7 Geonhar7 Dhenanal7 >apur7 Cuttac7 Gendrapara7

>agatsinghpur7 Puri7 Ghurda7 aagarh7 anam and aapati.

9ven though Phailin weaened slightl prior to land"all7 destructive winds well over 1$5 mph

+155 mph- and "looding rain o" at least 255 mm +) inches- pummeled the region. / crippling

storm surge o" at least 3 meters +15 "eet- is e0pected to have swamped the coast near and ust

northeast o" the point o" land"all.


13/17

The 4 maor reasons "or the disaster to have less impact +/nd o"course ndian overnment has to

e applauded "or the magni"icent wor-

1- 3**ective storm warnings y .ndian 4eteorological Department(.4D)

2- 3vacuations (that too 5uic0)

3- 6ocation o* Phailin7s land*all and its geography

4- The storm sustantially wea0ened prior to and during land*all


14/17

Cyclone Helen

Cclonic storm Helen #rida hit /ndhra Pradesh+ot again- coast near Bachilipatnam7

triggering heav rains and strong gales with speed reaching 155


15/17

Some Questions that passed through my mind. (Please avoid it unless you are just a

starter like me

1) 8hat is the di**erence etween 9hurricane:, 9cyclone: and 9typhoon:;

KHurricaneK7 KccloneK and KtphoonK are di""erent terms "or the same weather phenomenon

which is accompanied torrential rain and ma0imum sustained wind speeds +near centre-e0ceeding 11 ilometers per hour+mph-

n the western orth /tlantic7 central and eastern orth Paci"ic7 Cariean (ea and ul"

o" Be0ico7 such a weather phenomenon is called KhurricanesK.

n the western orth Paci"ic7 it is called KtphoonsK.

n the a o" engal and /raian (ea7 it is called KcclonesK.

n western (outh Paci"ic and southeast ndia *cean7 it is called severe tropical

cclones.E

n the southwest ndia *cean7 it is called tropical cclones.E


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2- 8hen do tropical cyclones occur;

The tphoon season in the western orth Paci"ic region tpicall runs "rom Ba to

ovemer. The /mericas'Cariean hurricane season runs "rom >une 1 to ovemer 357peaing in /ugust and (eptemer. The cclone season in (outh Paci"ic and /ustralia

normall runs "rom ovemer to /pril. n the a o" engal and /raian (ea7 tropical

cclones usuall occur "rom /pril to >une7 and (eptemer to ovemer +Cclone Phalin*ct 12th2513-. The 9ast Coast o" /"rica normall e0periences tropical cclones "rom

ovemer to /pril.

Reasons *or Cyclone (.n a nutshell only)

/s warm7 moist airover the ocean rises up "rom the ocean sur"ace7 there is less air le"t near thesur"ace7 and this causes an area o" lower air pressure elow.

The air around this region has higher air pressure7 and so it rushes in to "ill the low pressure area

This air also ecomes warm and moist and so it rises7 too. The ccle eeps going.

,arm air rises7 the surrounding air swirls in to tae its place7 and so on. ,hen the warm moist

air rises7 it cools o""7 and the water in the air "orms clouds. The whole sstem o" clouds and windspins and grows7 ecause it is eing constantl "ed the oceanAs heat and water evaporating

"rom the sur"ace.

Cclones can onl "orm over warm waters in the tropical regions o" the oceans where the sea

temperatures are 2$.! degrees Celsius or higher +around )5 degrees #-

The occur in areas o" ver low pressure when air that is heated the sun rises rapidl7 and

ecomes saturated with moisture which then condenses into high thundercloud. /s the

atmosphere ecomes "avorale "or development +no wind shearing in the higher parts o" theatmosphere-7 normal thunder storms clump together. ,hen the hot air rises7 cooler air rushes in

to "ill the area le"t vacant the hot air. The Coriolis e""ecto" the 9arth spinning on its a0is

causes the air to spiral upwards with considerale "orce. This in turn causes the winds to rotate

"aster7 causing the tropical low to deepen in intensit into a tropical depression7 and eventuall acclone

Cclones are also characteri=ed strong winds7 et in their centre is a clear7 calm region called

the AeeA. ,hen the cclone continues its course7 and the winds return "rom the other direction7the ma seem to e more violent. The winds are not ust rotatingM there is also the e""ect o" thewarmer air continuall rising and cold air rushing in. That is wh the winds are so strong7 and

seem to move in all directions.

>ust "or "un +,hose gives names to cclone e.g Phalin 7 Helen or tphoon Haien-


17/17

The name list is proposed the ational Beteorological and Hdrological (ervices +BH(s-

o" ,B* Bemers o" a speci"ic region7 and approved the respective tropical cclone regional

odies at their annual'i

cyclone phalin, helen, haiyan and basic theory on clouds (1)

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