ob 5 - the potential application of alos palsar for coastal (nascon2010)

8/9/2019 Ob 5 - The Potential Application of Alos Palsar for Coastal (Nascon2010)

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Syazwani Mohd Yusop 1 , Khiruddin Abdullah 1 , Lim Hwee San 1 , Mohd Noordin Abu Bakar 1

1School of Physics, Universiti Sains

Malaysia, 11800 Penang, Malaysia


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~ Coastal zone plays an important role in peoples life recreation, leisure, foodsupply, livelihood, transport as well as medical.

~ Besides, more important, many economic activities are available at coastal zonesuch as fisheries, shipping, tourism and urban development.~ Coastal zone represents only 10% of the total earth surface. However, this limitedspace is filled with almost 50% of population .~ Nowadays, in Malaysia, most major towns lie in the coastal zone area. Thisdisproportionate percentage of the population lies in the limited coastal area alwaysput the area under intense pressures resulting from overexploitation or unsustainableuse of resources and land-based and sea-based pollution.

~ Therefore, the need to ensure that coastal ecologies continue to function leads to the

development of a serious environmental management and planning.~ Remote sensing satellites then grow steadily as an outstanding tools to collectinformation in support of coastal zone management because of their capabilities ofimaging any area of interest in a synoptic, systematic and repetitive manner.

~ After many years, various radar imaging satellites were created and in 2006, ALOSPALSAR, which is operated in the L-band was born.


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~ In 2006, PALSAR was born to be an improved system that replaces Japans earlier L -band radar satellite system, Japanese Earth Resources Satellite 1 (JERS-1).

Figure 1 PALSAR

~ PALSAR is an active microwave sensor which is not affected by weather conditionsand can be operated both day time and night time.

~ ALOS, which carries PALSAR revolves around the earth in every 100 minutes or 14times a day. It returns to the original path (repeat cycle) in every 46 days.


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Main Characteristics of PALSAR

Mode Fine ScanSAR Polarimetric

Center Frequency 1270MHz(L-band)

Bandwidth 28MHz 14MHz 14,28MHz 14MHz

Polarization HH or VV HH+HV orVV+VH

HH or VV HH+HV+VH+VV

Incidence angle 8 ~ 60deg. 8 ~ 60deg. 18 ~ 43deg. 8 ~ 30deg.

Range Resolution 7 ~ 44m 14 ~ 88m 100m 24 ~ 89m

Swath 40 ~ 70km 40 ~ 70km 250 ~ 350km 20 ~ 65km

Quantization 5bits 5bits 5bits 3 or 5bits

Data rate 240Mbps 240Mbps 120Mbps, 240Mbps 240Mbps

Table 1 Main characteristics of PALSAR

~ There are about three primary methods of SAR outlined for the effective use ofPALSAR data (ERSDAC, 2006).

~ The methods are backscattering coefficient analysis , interferometry processing andpolarimetric data processing .


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~ Oil slick detection on Hebei Spirit oil spill incident- On 7 December 2007, a massive oil spill incident had occurred on the coast of YellowSea in South Korea.- Approximately 10,000 tons of crude oil was spilled in the sea after a barge collidedwith the anchored Hebei Spirit oil tanker.- Korea government had collected all imageries over the area from available SARsensors; ALOS PALSAR, ENVISAT, ASA, ERS-2, RADARSAT-1 and TerraSAR-Xfrom 9 December 2007 to 25 December 2007.- By using full polarization and ScanSAR mode of ALOS PALSAR and combining thedata with other satellites , damping ratio comparison of wind speed and wave number

were computed and measured.- With L-band retrieval and L-band wind comparison , the strong wind and current onthose time were detected.- To detect the oil slick, several processes such as land masking, adaptivethresholding and clustering and classification were performed to monitor the

movement of the oil slick around the area.


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~ Vietnam oil spill- Oil spill in many coastal provinces in Vietnam has become urgent problem for thegovernment.

- Image Analysis System for Remote Sensing WinASEAN, Department ofEnvironmental Information Study and Analysis (EISA), Institute of Geography hadanalysed and detected oil spill on PALSAR data.

- Through 26 scenes analysis from December 2006 to April 2007, the experts haddetected 14 oil spills on 7 scenes (Geoinfo, 2006).

Figure 2 ALOS PALSAR image of oilslick detection in the coastal zone ofVietnam (Geoinfo, 2006)


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~ Delineation of estuarine of Pamico Peninsula, Dare County,North Carolina, USA

- Wang and Allen (2007) applied an edge filtering model to delineate estuarineshorelines of the Pamlico Peninsula, Dare County, North Carolina, USA using the2006 ALOS PALSAR of HH mode and 1994 JERS-1 L-HH SAR data.

- To demonstrate the usage of the L-band ALOS PALSAR with HH mode data incoastal studies, they presented the delineation of shorelines in 1994 and 2006 throughedge extraction modeling, assess the accuracy of the extracted shorelines with high-spatial resolution aerial orthophotographs and ground data and quantify theaveraged shoreline change between 1994 and 2006.

- This research is important as in nowadays, global climate change and sea level riseare among serious environmental problems.


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The end result of ALOS PALSAR data can be achieved by applying some stages ofwork:

a.) Collection and compilation of early information about locations of research of pastand present records.b.) Data collection and field investigation and measurement .

c.) Pre-processing data

~ applying radiometric calibration to convert the digital numbers into backscattering coefficient~ speckle reduction

d.) Data processing ~

To monitor the oil slick migration, land masking by digital elevation model (DEM)can be applied. After that, clustering and classification image can be made (Kim et al.,2008).~ ALOS PALSAR also can be processed towards an automated ocean featuredetection, extraction and classification scheme (Wu S.Y. and Liu A.K., 2003).


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~ The physical characteristics of the ocean can be seen through the image by applying certain processes into the image.

in open oceans, the lighterappearance is referred to rougher sea

that always results from high winds

~ Applying texture analysis to the image

the rougher sea surface also can bereferred to internal waves andcurrent but their existence is muchless frequent

the darker appearance is referred tosmoother sea resulted from lowwind condition.


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~ The surface manifestation of activities such as wave-current interaction, wavedamping and atmospheric instability can be used to be used to identify fronts fromSAR imagery (Wu S.Y. and Liu A.K., 2003).

~ The interactions of current and bottom and waves and currents are hard to beinterpreted in ALOS PALSAR image but, high and low wind speed are the keys todetect internal wave .

~ The combination of technologies of fast fourier transforms with wavelet transformcan be applied to analyse the manifestation of internal wave .

~ When a part of ocean surfaced is covered by spilled oil , the area generates fewerripples than the surrounding area and the backscatter appears weaker over the area(ERSDAC, 2006).

~ Waves behind a sailing ship causing weak backscatter as the generation of ripplesis reduces. It shows the capabilities of ALOS PALSAR to detect ships .

~ Although radar image acquisition and analysis technique have been developed to ahigh degree of sophistication, the application of radar technology is still in activestate of advancement.


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~ Due to the increasing concern and pressure towards the future of the coastal zone,ALOS PALSAR is obviously can provide valuable data and information forenvironmental monitoring on earth and natural disasters.

~ ALOS PALSAR also does not affected by weather conditions and cloud, so it iscapable to make a huge contribution to the earth by providing a systematic, routineglobal monitoring of nearly all earths land surface and coastal zone.

~ The development and implementation of an advanced coastal ocean monitoring ofALOS PALSAR with its underlying improved knowledge of dominant coastal oceanprocess will contribute to the understanding of economic development and socialimpact of the coastal environment.


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~ We would like to thank the academic staff who encouraged usto do this beneficial and interesting research. Thanks alsoextended to USM for support and encouragement .


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ob 5 - the potential application of alos palsar for coastal (nascon2010)

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