Small viscosity behavior of a homogeneous, quasi-geostrophic, ocean circulation model

Insensitivity to turbulent closure in the wind-driven nonlinear Stommel-Mun k model is addressed theoretically and numerically. The QG energy equation is used to show that, with the assumption that the maximum velocities occur at inertial length scales or smaller, a Sverdrup interior is consistent wi th the small Rossby number assumption only when the frictional parameters e xceed critical values. For frictional parameters smaller than these values, valid solutions must decrease the energy source. This is possible for non- Sverdrup solutions since the energy source is dependent on the solution. Th e steady-state behavior of the model was investigated via a pseudo-arclengt h continuation algorithm. Dependence on the boundary layer Reynolds number, Re, was investigated by varying the eddy viscosity for fixed wind forcing. A tendency to decrease the energy source was found for solutions that are nonsymmetric about the center latitude. Antisymmetric solutions displayed t he opposite behavior and diverged more quickly with increasing Re. The robu stness of the results to dynamic boundary condition, symmetry and strength of wind stress, time dependence and bottom friction were tested. Some aspec ts of the nonsymmetric solutions appeared insensitive to Re.