Seasonal and spatial variability of IRS-P4 OCM (Oceansat-1) derived aerosol and its impact on surface water chlorophyll-a in the Bay of Bengal

Abstract

Observation made to study the aerosol pattern retrieved from the 865nm central wavelength band of Indian Remote Sensing satellite, IRS-P4 OCM (Oceansat-1) images. Aerosol concentration found higher during December (Northeast monsoon) over Bay of Bengal off Sundarbans with distinct plume. The aerosol optical depth (AOD) ranged 0.2- 0.85 in the image of December 24, 2002. Decreasing-trend observed towards offshore with AOD ~0.45. To understand its link with biological productivity, the ocean surface chlorophyll retrieved from seasonal datasets during April, June, October and December 2002. December has shown very high chlorophyll >2.0mg/m3, compared to other seasonal-months with aerosol plume from west to east, towards offshore. High wind speed (~6-8m/sec) and its direction played the role to move the aerosol towards offshore. Similar aerosol plumes observed during December 2003 and 2004.