[19-May-2026] Parc, L., Bonjean, F., Boutin, J., Vergely, J.-L., Guimbard, S., and Rouffi, F. Sea Surface Salinity (SSS) is an Essential Climate Variable (ECV) that plays a key role in the global thermohaline circulation, the hydrological cycle as well as the upper-ocean carbonate system and air-sea exchanges. Owing to its global coverage, satellite-based remote sensing of SSS is a key tool for monitoring this ECV. Since 2010, several missions have been successfully operated, starting with the Soil Moisture and Ocean Salinity (SMOS) mission launched by ESA, followed by Aquarius and Soil Moisture Active Passive (SMAP) missions developed by NASA. Thus, using these satellite measurements, this project aims to produce an SSS Climate Data Record (CDR) over the 2010-2024 period and a near-real-time Interim CDR (ICDR) from 2025 onward. Building on algorithms developed in the ESA Climate Change Initiative Salinity Project (CCI+SSS), monthly L4 SSS products at 50 km resolution will be provided twice a month on a 0,25° spatial grid through the Copernicus Climate Change Service (C3S). By being compliant with ECMWF and C3S technical standards, and aligned with GCOS requirements, these products are designed for climate monitoring, reanalysis and modelling applications.