Observation-based surface-forced water mass transformation benchmarks for ocean model evaluation

These datasets contains observation-based estimates of surface-forced water mass transformation (WMT) intended as benchmarks for evaluating ocean and coupled climate models. Transformation rates are provided globally and for the subpolar North Atlantic (SPNA), decomposed into subregional contributions and into heat and freshwater components. Contents: Eight observation-based WMT_sfc benchmarks formed from all combinations of two atmospheric forcing products (COREv2, JRA55-do), two sea surface temperature products (Hadley-OI, OISSTv2.1), and two sea surface salinity products (EN.4.2.2, Ishii). Accompanying surface heat and freshwater flux fields (four of each) computed with the CESM2 coupler bulk formulae are included. Method: Surface turbulent and radiative fluxes were computed in the CESM2 coupler, pairing each atmospheric forcing product with each SST product so that heat fluxes and surface density use a consistent SST. Net freshwater flux is P − E + R, with precipitation and runoff taken from the forcing product and evaporation from the coupler bulk formula; solid (land-ice) runoff is retained and contributes to the net heat flux through the latent heat of fusion. Sea ice freshwater, salt, and heat fluxes are excluded from the observation-based benchmarks. All fields are on the nominal-1° CESM2 ocean grid at monthly resolution Temporal coverage: 1982–2009 Provenance: Derived from public-domain observational, reanalysis, and state estimate products: COREv2, JRA55-do, Hadley-OI (SST and sea ice concentration), OISSTv2.1, EN.4.2.2, and Ishii.