A simulation of the Southern North Sea in comparison with measurements from the North Sea Project. Part 1: Temperature

The accurate simulation of the annual cycle and vertical structure of temperature is crucial to biological and water quality modelling in shelf-seas. As a precursor to these applications, we present a three-dimensional baroclinic simulation of the southern North Sea at the time of the North Sea Project (NSP), with density controlled by a prognostically evolving temperature field forced by surface heat fluxes from bulk formulae. The model results are compared, on a point for point basis, with CTD data from the NSP. The annual cycles in mean temperature, mean surface to bed temperature difference and mean thermocline depth, and the extent of the summer stratification are found to be in good agreement. Overall, the correlation between modelled and observed temperature is r2=0.95 for the depth mean component and r2=0.64 for the depth varying component. The rms deviation is about 1 degree. We assess the sources of these errors and the performance of the Mellor-Yamada level 2.5 turbulence closure as implemented in this model.