The dataset is a 20 year experiment using a NEMO-based 1/12 degree grid spacing model of the Southern Ocean as part of the ORCHESTRA (Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports) LTS-M project. It uses the NEMO "extended" grid, although ice cavities are closed. The model was run on Archer, the national HPC platform. The dataset covers the full length of the model run and includes regular (5 day mean) output of the model state, as well as more frequent (1 day mean) output of surface variables and fluxes and 1 month mean of more extensive transport diagnostics. The experiment neglects the ocean surface current in the bulk formula calculations for surface fluxes, so-called absolute wind stress. It starts from the end of 1987 of JRA55IAF (Munday et al., 2021).

Forced by JRA55-do, an interannually-varying forcing set (Tsujino et al., 2018). With some additional forcing as supplied by the UK Met Office (freshwater runoff, tidal friction, geothermal heating) and additional freshwater runoff to suppress polynya formation.