Polarization effects in the radiometric calibration of earth remote sensing satellites

Abstract

Recent efforts in Earth remote sensing have focused on accurately measuring top-of-atmosphere and surface leaving radiances. One factor that must be accounted for in the radiometric calibration of an Earth remote sensing satellite is the polarization of the radiance. This dissertation provides a comprehensive analysis of how polarization has an impact on the radiometric calibration of visible through long wave infrared Earth remote sensing satellites (0.4 through ∼15 μm). The first part of this dissertation concentrates on reviewing the current status of calibration and of polarization measurements in Earth remote sensing. It provides a comprehensive review of polarization in Earth scenes, calibration targets, and the sensitivity of instruments. The second part examines how polarization affects calibration during the application of the calibration coefficients. One must account for the differences in polarization between the calibration target, used to determine the calibration coefficients, and the scene itself. This dissertation derives the impact of polarization on the radiometric calibration coefficients using both the Stokes vector and the Jones vector formalisms and accounts for the instrument polarization sensitivity, calibration target polarization, and scene polarization through normalization. Using these derived results, the impacts of polarization on radiometric uncertainty are calculated for the family of theoretical cases and for cases based on literature data. The third part of this dissertation examines how the polarization response of an instrument can affect the calibration by creating a variation in the response vs. scan angle (RVS). It derives the mathematical relationship between the polarization response of an instrument and its response vs. scan angle. It examines the correlation between the two using MODIS pre-launch system level polarization and RVS measurement data and derives the sensitivity of the RVS to aft optics polarization. This establishes when scan mirror data is sufficient to characterize RVS and when a system level measurement is required. This dissertation then examines potential ways to determine the instrument's polarization response and response vs. scan angle post-launch. Finally, this dissertation identifies sensitivity thresholds in both cases and summarizes when polarization should be accounted for in radiometric calibration. Potential areas for future advancement of the field are discussed.