Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 10 2 2010 10.5194/acp-10-383-2010 http://www.atmos-chem-phys.net/10/383/2010/ http://www.atmos-chem-phys.net/10/383/2010/acp-10-383-2010.html http://www.atmos-chem-phys.net/10/383/2010/acp-10-383-2010.pdf 383 396 2010-01-18 The impact of aerosols on polarized sky radiance: model development, validation, and applications C. Emde claudia.emde@dlr.de R. Buras B. Mayer M. Blumthaler Institut für Physik der Atmosphäre, Deutsches Zentrum für Luft- und Raumfahrt, Oberpfaffenhofen, Germany Sektion für Biomedizinische Physik, Medizinische Universität Innsbruck, Innsbruck, Austria now at: Meteorologisches Institut, Ludwig-Maximilians-Universität, München, Germany Although solar radiation initially is unpolarized when entering the Earth's atmosphere, it is polarized by scattering processes with molecules, water droplets, ice crystals, and aerosols. Hence, measurements of the polarization state of radiation can be used to improve remote sensing of aerosols and clouds. The analysis of polarized radiance measurements requires an accurate radiative transfer model. To this end, a new efficient and flexible three-dimensional Monte Carlo code to compute polarized radiances has been developed and implemented into MYSTIC (Monte Carlo code for the phYSically correct Tracing of photons In Cloudy atmospheres). The code has been extensively validated against published benchmark results. The polarized downwelling radiation field is calculated for various aerosol types showing the high sensitivity of polarized ultraviolet radiances to the particle microphysics. Model simulations are compared to ground based measurements and found to be qualitatively in good agreement. 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