The Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) Version 1 Aerosol Extinction Retrieval Algorithm: Theoretical Basis
Abstract. The theoretical basis of the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) Version 1 aerosol extinction (AE) retrieval algorithm is presented. The algorithm uses an assumed bi-modal log-normal aerosol size distribution to retrieve AE profiles at 675 nm from OMPS LP radiance measurements. A first-guess AE profile is updated by iteration using the Chahine non-linear relaxation method, based on comparisons between the measured radiance profile at 675 nm and the radiance profile calculated by the Gauss-Seidel Limb Scattering (GSLS) radiative transfer model for a spherical-shell atmosphere. This algorithm is discussed in the context of previous limb-scattering AE retrieval algorithms, and the most significant error sources are enumerated. The retrieval algorithm is limited primarily by uncertainty about the aerosol phase function, and by horizontal variations in aerosol extinction, which violate the spherical-shell atmosphere assumed in the Version 1 algorithm.