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Detection and analysis of growth of Sea - Ice using MSMR brightness temperature data
In the process of complete analysis of the phenomenon, Aerospace Department, University of Colorado provided U.S. National Ice Center charts for the month of October 2000 [Figure 5] for East Siberian Sea, one of the areas where the Tb change was noticed.
Figure 5. Ice Analysis Chart for East Siberian Sea (latitude 70°N to 80°N and longitude 135°E to 175°E [Source: U.S. National/Naval Ice Center] Conclusions The polar brightness temperature maps [Figure 4] show that the Tb has increased by about 60-70 degrees over a short interval of 15 days after which it remains constant for about eight months and then decreases gradually. The gradual decrease in Tb from autumn through winter is a result of the accumulation and evolution of snow on the sea-ice. The ice charts help to infer that the sea-ice accumulation takes place with in a short time and it takes about a year to become ice-free ocean. The rates of freeze-up and ice retreat vary somewhat from year to year, but the decrease is more gradual in spring through summer. In the latter case, some of the changes in Tb are due to surface melt and accumulation of melt water on the sea-ice. The patterns (changes in Tb, polarization, and spatial patterns and location) look almost like those associated with the change from ice-free oceans, to the oceans covered by sea-ice. It is supposed that the same pattern must be getting repeated every year. However, further work needs to be done using SMMR and SSM/I data. The brightness temperature maps of whole polar region can be prepared at regular intervals of about 15 days to locate some more areas having similar phenomenon of rapid polar sea-ice freeze up. Moreover, comparison of the results so obtained with data of some more years would throw light on the undiscovered facts. Thus the determination of the kind of ice present in the sea is extremely significant for shipping and transportation, as it would save huge amounts of life and property from being lost in any accidents caused by icebergs and glaciers in the higher latitudes. Further work in this direction would therefore be useful in guiding ships in the future by helping them to follow the path free from all obstacles and lingering hazards, using communication satellites. Efforts to prepare a model for sea-ice thickness determination and a thermodynamic model to predict the global climatic changes can also be made. References
www.isro.org/irsp4 Official web site of Indian Remote Sensing Organization. www.csre.iitb.ernet.in/isro/irs-p4 Official website of CSRE, IIT-Bombay. www.nrsaftp.gov.in/msmr_help Official website of National Remote Sensing Agency, Department of Space, Government of India, Hyderabad for data download service. www.ioccg.org/general/ocm/ocm Official website of International Ocean Color Coordinating Group. www.gisdevelopment.net/technology/rs/techrs0009 Appendix
Table 2. GPP and Frequencies used for Grid in IRS-P4
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