Sensitivity analysis of single-angle polarization reflectance observed by satellite

Abstract

Two channels of the Cloud Aerosol Polarimetric Imager, onboard the TanSat-Chinese carbon dioxide observation satellite, are designed to detect the polarization state of radiation reflected by the earth-atmosphere system in a single-viewing angle. Aiming to understand how the earth and atmospheric parameters affect the polarization state of radiation, we conduct a sensitivity analysis of the polarized reflectance at the top of atmosphere (TOA) with respect to the aerosol microphysical parameters, atmospheric profiles, and surface polarization properties. It is found that (1) the TOA polarization reflectance at 0.66 μm is most sensitive to the real part of the aerosol complex refractive index, the mean radius of the fine mode aerosol particles, as well as atmospheric pressure and temperature profiles; (2) the TOA polarization reflectance at 1.64 μm is sensitive to the volume ratio between the coarse mode and fine mode particles as well, but it is not sensitive to atmospheric profiles; and (3) surface polarization properties have a relatively weak influence on the TOA polarization reflectance at both 0.66 and 1.64 μm.