Characteristics of spectral optical depths and size distributions of aerosols over tropical oceanic regions

The characteristics of atmospheric aerosols and their dependence on meterological parameters over different marine environments are examined using columnar size distributions retrieved from spectral optical depth estimates over coastal and remote regions of the Arabian sea and equatorial Indian Ocean. In the near coastal regions, the aerosol size distribution is dependent on surface wind direction, showing the influence of proximity to the continent under continental wind conditions. Marine aerosols dominate and the large particle mode becomes well established in the far coastal and remote ocean environments. The optical depths and size parameters depend on surface wind speed. The overall aerosol loading decreases and the relative concentration of coarse particle increases as one moves to oceanic regions farther from the coast. The implications of these findings are discussed. (C) 1998 Elsevier Science Ltd. All rights: reserved.