The inter-comparison of major satellite aerosol retrieval algorithms using simulated intensity and polarization characteristics of reflected light

Remote sensing of aerosol from space is a chal- lenging and typically underdetermined retrieval task, requir- ing many assumptions to be made with respect to the aerosol and surface models. Therefore, the quality of a priori in- formation plays a central role in any retrieval process (apart from the cloud screening procedure and the forward radiative transfer model, which to be most accurate should include the treatment of light polarization and molecular-aerosol cou- pling). In this paper the performance of various algorithms with respect to the of spectral aerosol optical thickness de- termination from optical spaceborne measurements is stud- ied. The algorithms are based on various types of measure- ments (spectral, angular, polarization, or some combination of these). It is confirmed that multiangular spectropolarimet- ric measurements provide more powerful constraints com- pared to spectral intensity measurements alone, particularly those acquired at a single view angle and which rely on a pri- ori assumptions regarding the particle phase function in the retrieval process.