Monday 16 Mar 2015: Ellipsoidal vortices in rotating stratified fluids: beyond the quasi-geostrophic approximation
Yue-Kin Tsang - University of Exeter
Harrison 103 15:00-16:00
As a model of lens-like vortices observed in the ocean, we examine numerically the dynamics of an ellipsoidal volume of uniform potential vorticity in a non-hydrostatic rotating stratified fluid at finite Rossby number, thus extending previous work which mostly focused on quasi-geostrophic vortex at vanishing Rossby number. Some consequences of the ageostrophic effects are enhanced stability in a cyclone and increased rotation rate for an anticyclone. When an vortex becomes unstable, we observe that the emission of inertia-gravity waves during its nonlinear evolution is negligible, thus the vortex and any associated instabilities are in an ageostrophically balanced state.