Glenn Flierl, John Marshall, WHOI and MIT

Title Unknown

We are using numerical models to study the interactions of physical and biological dynamics on various scales, from small scale patchiness, to mesoscale motions, to the Circumpolar Current. Parameterizations of unresolved processes are an essential part of any model; however, present parameterizations of tracer transports employed to infer rates of oceanic uptake are unsatisfactory. Tracers (e.g., nitrates and carbon) are advected not by the Eulerian mean flow (as assumed in current biogeochemical models), but rather by the "transformed Eulerian mean", a flow which includes nonzero residual circulation due to mesoscale eddies. In addition, biological activity in the euphotic zone is patchy, not only because the supply of nutrients to the euphotic zone is locally dependent on mesoscale features, but also because of internal dynamics of the biological populations. Detailed patchiness models will be used to determine the appropriate representation of such fields and rate processes associated with these organisms in larger scale models. Eddy resolving process models will be used to examine the role of patchiness and eddies in chemical and biological transports and motivate parameterizations for larger scale models. The understanding gained from such studies will be incorporated into a global model of biogeochemical cycles based on the new ocean GCM developed at MIT. These modeling studies will be carried out in the light of the understanding of the circulation of the southern ocean and the growing database there.