[19p-S621-1~9] New developments in polarization measurement and control

▲ [19p-S621-4] Polarization of Skylight

〇Joseph A Shaw¹, Laura M Dahl¹, Nathan J Pust¹ (1.Montana State Univ.)

Keywords:polarization,skylight,aerosols

An all-sky polarization imager has been developed and used to measure spatial-spectral patterns of polarization in the atmosphere. This presentation will briefly describe the instrument and its measurements, including a discussion of the spectral variation of skylight polarization from 400 to 2500 nm wavelength. Skylight polarization can increase or decrease with wavelength, depending on the atmospheric aerosol content (atmospheric clarity) and underlying surface reflectance. With clean and moderately hazy atmospheric conditions, skylight polarization generally tends to increase slowly through the spectral range of approximately 400-1000 nm and decrease through the spectral range of 1000-2500 nm. The dominant parameters for predicting skylight polarization spectra in these two spectral bands are aerosol optical depth and aerosol size distribution, respectively. Surface reflectance also is a significant factor throughout both of these spectral bands.