First prototype for surface albedo retrieval based on sentinel-3 olci and slstr data in the framwork of copernicus climate change service

This work describes the different algorithmic steps used to retrieve the first Surface Albedo (SA) product based on Sentinel-3 (S-3) data in the framework of the Copernicus Climate Change Service (C3S). The atmospherically corrected Top-Of-Atmosphere (TOA) reflectances into Top-Of-Canopy (TOC) reflectances are brokered from Copernicus Global Land Service (CGLS). The BRDF inversion model transforms the TOC reflectances into model coefficients. Next, the spectral and angular integration steps are implemented, which take the latter coefficients as input to produce spectral and broadband albedo quantities. The preliminary validation of BSA broadband albedo for the total shortwave shows good overall spatio-temporal consistency with C3S PROBA-V SA products, and good spatial consistency with MCD43A3 C6 over the Iberian Peninsula (mean bias lower than 5%), with some underestimation of snow targets.