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Poster Session 3
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Monitoring of Forest Fires And Oil Pollution from Space
Ocean Oil Pollution Monitoring
In ocean pollution monitoring, ERS-2 and RADARAST SAR image are acquired., processed and analysed for detection of oil spills.In SAR images, the brightness of the sea surface is a measure of the sea surface roughness.Smooth sea surface appearsdark while the brightness increases as the sea surface becomes rougher. Oil films are very effective in damping wind-generated gravity-capillary short waves on the sea surface and hence they appear dark against a brighter background in SAR images.However,not all dark sea surface areas in SAR images are oil slicks. Sea surface may also appear dark due to natural slicks, low, sea surface wind speed, and other reasons. Contextual information such as the shapes and locations of the suspected oil slicks can help to avoid false detection. Other auxiliary data such as wind speeds are also helpful if available [9]. Fig. 7 shows two ERS SAR images illustrating oil slicks detected in the Gulf of Thailand and the south china Sea. In the left scene, a slick longer than 100 km runs diagonally across the image.
Fig.7: Examples of oil slicks detected in ERS SAR images over the Gulf of Thailand (left) and the south China Sea (right). © ESA 1996.
Statistics of oil-spills over the Straits of Malacca, south China Sea and other seas in the region have been compiled by analyzing over 2500 ERS SAR quicklook images (100-m resolution) of the region in CRISP's archive covering the period from September 1995 to May 1998. A total of 7218 slicks were detected, occurring in 1399 scenes (55% of the scenes surveyed). Most of the slicks were concentrated along the major ship routes. Areas with the most number of slicks per scene were found in the South China Sea and the Gulf of Thailand.
Conclusions
Remote sensing images acquired from satellites provide sypnotic views of the earth surface. Images from the SPOT and ERS satellites have been used in monitoring forest fires and in deriving burnt scar maps for damage assement. Synthetic aperture radar images from the ERS and RADARSAT satellites are useful for monitoring oil pollution in the ocean. Spatial distribution of oil slicks complied from ERS images show that most pollution occurs Along the major ship routes. Examples reported in this paper show that satellite remote sensing can play an important role in the monitoring of land and ocean environment.
Fig. 8: Spatial distribution of ocean oil pollution in the Southeast Asian waters derived from over 2500 ERS SAR scenes covering the period from September 1995 to May 1998.
Reference
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J.M. Robinson, Fire from space: Global fire evaluation using infrared remote sensing, Int. J. Remote Sensing 12, 3-24, 1991.
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M. Matson, G. Stephens and J. Robinson, fire detection using data from the NOAA-N satellites, Int. J. Remote Sensing 8, 961-970.
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J.P. Malingreau, the contribution of remote sensing to the global monitoring of fires in tropical and subtropical ecosystems, in "Fires in the tropical biota" ed. JD Goldammer, springer-Verllag, 1990, pp. 337-370.
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R.A. Ferrare, R.S. Fraser and Y.J. Kaufman, Satellite measurements of large-scale air pollution: Measurements of forest the smoke, J. Geophys. Res. 95(D7), 9911-9925, 1990.
-
S.C. Liew, O.K. Lim, L.K. Kwoh and H.Lim, A Study of the 1997 forest fires in South East Asia using SPOT quicklook mosaics, 1998 Int. Geosci. Remote Sensing Symp.
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T.LeToan, F. Ribbes, T. Hahn, N. Floury and U.R. Wasrin, Use of ERS-1 SAR data for forest monitoring in South Sumattra, Proc. 1996 Int. Geosci. Remote Sensing symp, 842-844, 1996.
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U. Segmuller and C.L. Werner, SAR interferometric signatures of forest, IEEE Trans. Geosci. Remote Sensing 33, 1153-1163, 1995.
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N. Stussi, S.C. Liew, L.K, Kwoh and H. Lim, Landcover classification using ERS-SAR/INSAR data over tropical areas, Proc. 1997 Int. Geosci. Remote Sensing symp. 813-815, 1997.
-
H.A. Hovland, J.A. Johannessen and G. Digranes, Slick detection in SAR images, Proc. 1994 Int. Geosci. Remote Sensing Symp., 2038-2040, 1994.
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