In this study, a vector radiative transfer model for the coupled ocean-atmosphere system with considerations of effects of the Earth curvature (named PCOART-SA) was developed using the pseudo-spherical approximation. Both downward and reflected solar beam radiation were corrected accounting for Earth curvature effects. Validation showed that the PCOART-SA results agreed well with literature benchmarks and the CDISORT and AccuRT model results. Based on PCOART-SA, Earth curvature effects on Rayleigh-scattering radiance including polarization were investigated. The results showed that the influence of Earth curvature increased rapidly with solar zenith angle, with influences up to 1%, 3%, and 12% for solar zenith angles at 75°, 80°, and 85°, respectively, which should be considered for high accuracy atmospheric correction. We also found that the Rayleigh-scattering look-up table in SeaDAS after version 7.2 showed significant bias at high solar zenith angles, which needs further investigations. Finally, using the PCOART-SA model, we generated Rayleigh-scattering lookup tables for Aqua/MODIS with considerations of Earth curvature effects, which can be directly used in SeaDAS.
He, X., K. Stamnes, Y. Bai, W. Li and D. Wang. Effects of Earth curvature on atmospheric correction for ocean color remote sensing. Remote Sensing of Environment, 2018, 209: 118-133.
