Validation of the CERES Edition 4A Surface-Only Flux Algorithms

The shortwave (SW) and longwave (LW) radiative fluxes at the surface are critical components of the surface energy budget. The CERES Single Scanner Footprint (SSF) product provides surface fluxes from two SW and three LW Surface-Only Flux Algorithms (SOFA) for the Aqua and Terra satellites. A seventeen-year record of fluxes from SOFA parameterized models is now available along with corresponding surface-based measurements from several high-quality networks. This combination provides a unique opportunity to examine the strengths and the weaknesses of these algorithms. The CERES ARM Validation Experiment (CAVE) has been providing long-term surface observations for the validation of the CERES products from networks like ARM, SURFRAD, and BSRN. Forty-four sites from these networks and distributed over the globe were used for validation of the downward fluxes. Validation results demonstrate that the CERES SOFA product is highly accurate. The LW bias for all three models is less than 5 Wm^-2 (2%). The SW models have an overall bias of less than 8 Wm^-2 (4%). All fluxes were evaluated for both clear-sky and cloudy-sky results and LW fluxes were evaluated for day and night separately. Results were also separated by surface type and the SW accuracy is found to be lower for the polar areas and some islands.