The Scottish Shelf Model (SSM) 3.02 27 Year Reanalysis, otherwise referred to as the Scottish Shelf Waters Reanalysis Service (SSW-RS), is a hindcast model, run from 1993 to 2019, covering the Scottish continental shelf waters as well as most of UK waters, the North Sea and the English Channel. The domain extends from approximately 48° - 62° N and 13° W - 13° E. The SSM 3.02 27 Year Reanalysis was developed and run by the National Oceanography Centre. The model output, which includes hourly horizontal currents and water elevation fields, daily mean fields of three-dimensional currents, temperature and salinity, on the unstructured model mesh, is available for download from https://gws-access.jasmin.ac.uk/public/ssw_rs/. Registration is required to access this data via the SSW-RS website: www.tinyurl.com/SSW-Reanalysis.

The SSM implements the Finite Volume Community Ocean Model which utilises an unstructured computational grid enabling the model to resolve many small scale coastal features. The horizontal resolution ranges from 1 km at the coast to 20 km at the outer boundary.
New to version 3.02 is a hybrid sigma layer scheme. The vertical water column is resolved using 20 standard terrain following sigma layers (each representing 5% of the water column) in areas shallower than the 120 m isobath. In areas deeper than the 120 m isobath, the water column is resolved with 5 fixed layers at the surface and 2 fixed layers at the bottom. The surface layers are 3, 6, 7, 7 and 7 m thick and reside at 1.5, 6, 12.5, 19.5, 26.5 m depth. The bottom layers are both 6 m thick and reside 3 and 9 m above the bottom. The remaining 13 sigma layers are of equal spacing for the mid depths. Products provided by Copernicus Marine Service were used to force the model at open boundaries, to provide sea surface temperature data assimilation and to calibrate/validate the model.