Modeling polarized radiative transfer for improved atmospheric aerosol retrieval with OSIRIS limb scattered spectra

Abstract

Retrievals of atmospheric information from satellite observations permit the investigation of otherwise inaccessible atmospheric phenomena. The recovery of this information from optical instrumentation located in orbit requires both an inversion algorithm like the Saskatchewan Multiplicative Algebraic Reconstruction Technique and a forward model like the SASKTRAN radiative transfer model. These are used together at the University of Saskatchewan to retrieve sulphate aerosol extinction profiles from the radiance measurements made by the Canadian built OSIRIS instrument. Although these retrievals are highly successful the process currently does not consider the polarization of light or OSIRIS's polarization sensitivities because SASKTRAN is a scalar model. In this work the development of a vector version of SASKTRAN that can perform polarized radiative transfer calculations is presented.

The vector SASKTRAN's results compare favorably with vector SCIATRAN, another polarized model that is in development at the University of Bremen. Comparisons of the stratospheric aerosol retrieval vectors generated from the scalar and vector SASKTRAN results indicate that the polarized calculations are an important factor in future work to improve the aerosol retrievals and to recover particle size or composition information.