A 2-DIMENSIONAL MODEL FOR QUASI-GEOSTROPHIC FLOW - COMPARISON WITH THE 2-DIMENSIONAL EULER FLOW

A simple two-dimensional model for quasigeostrophic flow is contrasted with the two-dimensional incompressible Euler equations. The model ar ises under the assumptions of fast rotation, uniform stratification an d uniform potential vorticity. It is found that the more local feed-ba ck of the quasigeostrophic model gives rise to strongly nonlinear fron t formation, as opposed to two-dimensional Euler, where the steepening process of mature fronts obeys a nonlocal, nearly Linear mechanism.