Ocean Reanalysis
D5. Coastal processes, sea-level, cryosphere and ocean observation scienceDefinition
Long-term ocean state estimate combining models and observations.
An ocean reanalysis reconstructs the past state of the ocean by assimilating historical observations (Argo profiles, satellite altimetry and SST, moorings, and ship data) into a circulation model, producing a gridded, dynamically consistent record of temperature, salinity, currents, and sea level. Products like GLORYS from Mercator Ocean and the Copernicus Marine Service feed climate studies and operational forecasting. They fill the gaps between sparse observations but inherit the biases of both the model and the input data.