Aerosol properties over the Indian Ocean Experiment (INDOEX) campaign area retrieved from ATSR-2

Aerosol retrieved algorithms for ATSR-2 have been applied over land and water using data from the Indian Ocean Experiment (INDOEX) Intensive Field Phase (IFP) in February and March 1999. The goal was the extension of the ATSR-2 algorithms, developed for application over the U.S. east coast and Europe, to other areas with different types of aerosols and to explore the feasibility of deriving spatial variations in the aerosol composition. The ATSR-2 algorithm was extended with absorbing aerosols, and AERONET data were used to test the retrieved spectral aerosol optical depth (AOD). The resulting maps of AOD at 0.659 μm, Angstrom coefficient and urban/industrial aerosol contribution to the AOD over the ocean are evaluated by comparison with in situ data. AOD over land is in the range 0.18-0.45 with values up to 0.7 when biomass burning aerosol is present and decreases gradually over water with increasing fetch to 0.15 near the Intertropical Convergence Zone (ITCZ). Angstrom coefficients over land are in the range 1.5-2.0. Over water these values gradually decrease to almost zero. Over land urban/industrial aerosol dominates, and, as expected, over water the anthropogenic influence gradually decreases with fetch and the relative contribution of marine aerosol increases. South of the ITCZ the anthropogenic effect is negligible. Copyright 2006 by the American Geophysical Union.