Predicting the thermocline in a circulation model of the North sea — part I: model description, calibration and verification

A model is presented that allows the prognostic simulation of the temperature in the North Sea. An approach proposed by Kochergin (1987 Three-dimensional coastal ocean models, American Geophysical Union, pp. 201–208). to determine the vertical eddy diffusion and eddy viscosity was applied for the surface and bottom mixed layer. At the sea surface observed temperatures are prescribed (Dirichletʹs boundary condition). They contain the effect of all components determining the heat flux in the surface layer. This includes, besides all advective and diffusive heat fluxes in the surface layer, the net-heat flux through the sea surface. By this means it is possible to circumvent the uncertainties in the determination of the heat flux through the atmosphere-sea interface. A calibration and verification of the presented model is carried out by comparing the model results firstly with a time series of actual temperature profiles and secondly with a climatological monthly mean of the bottom water temperature.