M 311

Large-scale oceanic flows can often be described by quasi-geostrophic models. These are applicable if the Rossby number is small, as is the case in the earth’s atmosphere and oceans. Geostrophy means that the Coriolis force is balanced by the horizontal pressure gradient, thus allowing for additional simplifications compared to the (hydrostatic) Navier–Stokes equations. In this talk, I will illustrate the derivation of such systems, discuss the imposition of boundary conditions and show preliminary numerical results based on global spectral methods. The models and solvers we develop are interesting for a number of applications, in which the effects of bottom topography have been neglected thus far. We hope to fill these gaps in the course of this project. First, we plan to study how topography affects the spin-up of a stratified ocean at rest, for which there is a theoretical foundation in the case of flat bottoms.

Hennes Hajduk

Section for Meteorology and Oceanography (MetOs), University of Oslo (UiO), Norway