The Parameterization of Subgrid-Scale Heat Diffusion In Eddy-Resolved Ocean Circulation Models

Abstract

The two-layer quasigeostrophic model of Holland is modified to include a parameterization of subgrid-scale heat diffusion. Results from a sequence of simple, eddy-resolved calculations illustrate the effects of increasing heat diffusivities. It is clear that even rather small diffusion coefficients (small compared to the viscosity) cause important modifications of the eddy field and of the eddy generation process. In particular, heat diffusion can be very effective at diminishing the baroclinic signal associated with mesoscale processes, making it less likely that baroclinic instability processes can exceed damping.