Asian dust: Spatial and optical properties as seen by satellite ocean color sensors

Mineral dust-rich aerosol, such as of Saharan dust or Asian dust, is important in terms of its effect on radiation budget as well as a source of micro-nutrient in the oceanic phytoplankton ecosystem. In this paper, we introduce an empirical scheme for detecting dust aerosol over the ocean using satellite ocean color data such as of Sea Wide Field-of-View Scanner (SeaWiFS) or Ocean Color and Temperature Scanner (OCTS). The dust detection scheme in the paper uses estimated aerosol reflectance at 4 bands to detect spectral curvature in the aerosol reflectance. A series of dust index images over the north Pacific is derived from the SeaWiFS data obtained in April, 1998 when major Asian dust events were reported. The satellite-derived dust imagery is compared with the TOMS Aerosol Index imagery as well as results of dust transport simulation. The comparison reveals several small-scale differences although their dust distribution patterns show good agreement generally.