INERTIAL GYRE SOLUTIONS FROM A PRIMITIVE EQUATION OCEAN MODEL

A numerical exploration of inertial equilibrium states obtained with a primitive equation ocean model suggests that they can be described us ing statistical mechanics theory developed in the framework of quasi-g eostrophy, The performance of the numerical model is first assessed wi th respect to the quasi-geostrophic model considering a series of expe riments in the quasi-geostrophic range, in a closed basin with hat bot tom and varying Rossby numbers. The results show that our model is con sistent with the quasi-geostrophic model even in terms of dependence f rom boundary conditions and eddy viscosity values, and that the free s urface contribution is negligible. As in the quasi-geostrophic experim ents, a tendency toward Fofonoff flows is observed. This tendency rema ins in a second series of experiments performed outside the quasi-geos trophic range, namely with flows with higher Rossby numbers and with s teep topography, characterized by sloping boundaries with an order one fractional change in the depth. It is only close to the boundaries th at ageostrophic effects modify the flows. In conclusion, the fact that statistical mechanics theory, initially developed in the framework of quasi-geostrophy, holds for more realistic flows with steep topograph y supports development of subgrid scale parameterizations based on sta tistical mechanics theory, to be used in realistic general circulation models.