Retrieval of Aerosol Optical Depth from Oceansat-2 OCM

Abstract

Aerosols are the tiny suspended particles in the atmosphere playing a major role in influencing the net radiation budget of the earth. The aerosols also affect cloud microphysics and those with land origin, possibly reduce the monsoon rainfall. Dynamic and diverse nature of the aerosols varies according to different locations. The aerosols originating due to desert dust, rural atmospheric situations, urban pollutants and marine areas have wide variations and display specific characteristics. Routine monitoring of aerosol events and their subsequent dispersal pattern are important in order to understand their role in climatic process. Hence, it is very important to study the aerosols and their retrieval strategy from the ocean colour remote sensing sensors. The satellite sensors provide platform for making observations covering large area as also their short-term and frequent repetivity. Ocean-colour sensors e.g. CZCS, SeaWiFS, MODIS, POLDAR, Oceansat-1 & 2 OCM have been used to study aerosols, apart from being used to study ocean-colour. Most of the ocean-colour sensors are equipped with a few additional near infrared (NIR) bands ( λ > 700 nm), which are helpful in providing vital information on atmospheric aerosols due to strong absorption by water in NIR wavelengths. The present work is an attempt to study the temporal and spatial variations of Aerosol Optical Depth (AOD) over the Bay of Bengal using Oceansat-2 Ocean Colour Monitor (OCM).