Atmospheric correction scheme for ocean color remote sensing in consideration to Asian dust aerosol

The transport of Asian dust particles (KOSA) through the atmosphere to the Northwest Pacific is the most intensive one of this kind on the globe and is important in terms of the geochemical ocean cycle. The dust particles are also known to affect atmospheric correction process of satellite ocean color data, resulting in erroneous estimation of phytoplankton pigment concentration which, in turn, affects the proper evaluation of primary production in the area. Considering this problem, the authors propose a modified atmospheric correction scheme for Nimbus-7/CZCS data, based on the standard Gordon´s (1983) algorithm. To process the imagery the authors assumed that normalized water-leaving radiance at 550 nm was constant and that aerosol single scattering albedo at 550 nm covaries with the spectral dependency of aerosol scatterance. The single scattering albedo and the optical depth of aerosol at 550 nm are determined from the 550 nm and 670 nm channels by pixel-wise iterative procedures. The scheme processes data for other channels by assuming a spectral dependency of aerosol single scattering albedo modeled after obtaining a typical Asian dust image. The method was applied to selected Japanese CZCS scenes, and the derived phytoplankton pigment concentration was compared with Gordon´s algorithm. For images with well-behaved atmospheric condition, the results in phytoplankton pigment concentration mere overestimated by Gordon´s method. The scheme is considered useful to correct for the atmospheric effect of absorptive aerosol