Global Daytime Mean Shortwave Flux Consistency Under Varying EPIC Viewing Geometries

One of the most crucial tasks measuring top-of-atmosphere (TOA) radiative flux is to understand relationships between radiances and fluxes, particularly for reflected shortwave (SW) fluxes. The radiance-to-flux conversion accomplished by constructing angular distribution models (ADMs). This depends on solar-viewing geometries as well scene types within field view. To date, comprehensive observation-based ADMs are developed using Clouds Earth’s Radiant Energy System (CERES) observations. These used derive TOA SW fluxes from CERES other Earth radiation budget instruments which observe mostly side-scattering angles. Polychromatic Imaging Camera (EPIC) onboard Deep Space Climate Observatory observes at Lagrange-1 point in near-backscattering directions offers a testbed ADMs. As EPIC relative azimuth angles change 168 ◦ 178 , global daytime mean can increase much 10% though no notable cloud changes observed. derived after considering radiance anisotropies show smaller differences (<1%), indicating increases due viewing geometries. Furthermore, annual agree with equivalents 0.5 Wm −2 root-mean-square errors less than 3.0 . Consistency inverted very different indicates that accurately quantify anisotropy be inversion perspectives.