Validation of DSCOVR-based albedo estimate using a weather model

The Deep Space Climate Observatory (DSCOVR) is located near the Lagrangian L1 point of the Earth. Their EPIC images indicate exceptionally large values of the Earth's planetary albedo in December 2020, having daily average surged above 0.320 for consecutive three weeks. Independent evaluation of the Earth’s albedo using a numerical weather prediction model (OpenIFS of ECMWF) suggests that this is an over-estimate. Given the difference between satellite-based and model-based albedo estimates, the reconstructed from images top-of-atmosphere short-wave radiosity is over-estimated. We suggest the discrepancy is explained by a weakness of short-wave angular distribution models (ADMs) based on Clouds and the Earth's Radiant Energy System’s The Tropical Rainfall Measuring Mission (CERES/TRMM) in full back-scattering geometry. This conclusion is supported by disk-integrated short-wave anisotropy factors in December 2020, estimated using CERES ADMs, being lower than measured by NIST Advanced Radiometer (NISTAR).