Aerosol spectral optical depths over the Bay of Bengal: role of transport

Recent experiments have shown the potential role of air masses in transporting aerosols to locations far away from source regions. Despite the importance of the Bay of Bengal to Indian climate and monsoon, no serious aerosol observations are available for this region. Extensive aerosol optical depth estimates, made for the first time from an island location, Port Blair (11.63°N; 92.71°E) in the Bay of Bengal, during the Indian winter of 2002, are used to examine the impact of air trajectories in modifying the optical depths and their spectral dependences. The results are examined for their distinctiveness with respect to the origin as well as transport. It is seen that the trajectories arriving from the regions east of the station (South China, Thailand, Laos, Cambodia, Vietnam, Burma) are richer in aerosol abundance, more in the sub micron size range, than those arriving from the west, across the Indian landmass