Retrieval of aerosol properties over the ocean using multispectral and multiangle photopolarimetric measurements from the Research Scanning Polarimeter

The evaluation of the direct and indirect aerosol forcings of climate requi res precise knowledge of the aerosol optical thickness, size distribution, chemical composition, and number density. Global monitoring of these parame ters from satellites requires instruments that make full use of the informa tion content of the scattered solar radiation. In this paper we analyze mul tispectral and multiangle photopolarimetric observations performed with an airborne version of the Earth Observing Scanning Polarimeter over the ocean and demonstrate their exceptional retrieval potential. Using the 0.865- an d 2.250-mum channels, we are able to determine the parameters of a bimodal size distribution, identify the presence of water-soluble and sea salt part icles, and retrieve the optical thickness and column number density of aero sols. We also demonstrate that less comprehensive measurements by existing instruments would fail to provide retrievals of comparable completeness and accuracy.