A new regional model of the Subpolar Gyre based on NEMO4

The investigation is devoted to the development of a regional eddy-resolving model of the ocean of the Subpolar North Atlantic in order to reliably reproduce the components and properties of the Subpolar Gyre and the Atlantic meridional overturning circulation. Using the tools of the NEMO4 model, a configuration was created and, based on the literature, new parametrizations were proposed and implemented in the model: correction of the friction stress (current feedback for forced models), cool skin and warm sublayer in surface turbilent fluxes scheme. Also we formulated the best scheme of horizontal impulse advection from the point of view of reproducing mesoscale vortices. Last but noe least the local-sigma coordinate was implemented in the area of underwater cascading (overflow). For the first time, the eddy-resolving global ocean reanalysis GLORYS12V1 was validated against the independent observational data. The implementation of the local sigma coordinate allowed to reproduce the flow function of the Atlantic meridional overturning circulation in a model with a stepped representation of bathymetry. All the parametrization and scheme innovations led to an improvement in the solution, with the exception of the cool skin parametrization. Physical processes representation in the model is discussed.