The Dynamics of Geostrophic Vortices in the Presence of Nonaxisymmetric Forcing, with Application to the Stratospheric Polar Vortex

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The co-principal investigators will conduct a study of the dynamics of equivalent barotropic and baroclinic vortices, using a numerical method known as contour dynamics. This method is very attractive for studies of nonlinear processes, especially in terms of reducing computational requirements, but thus far has not been widely applied in atmospheric sciences studies. The motivation for the dynamical investigation is twofold. The practical motivation is the increased awareness of processes such as "breaking" and "filamentation" in the context of geophysical vortices, and particularly in the dynamics of the stratospheric polar vortex. Most of our current rudimentary understanding of such phenomena derives from barotropic models. The theoretical motivation stems from recent studies which show that the dynamics of breaking baroclinic or equivalent barotropic vortices may differ significantly from the barotropic case. The researchers will investigate the implications of these results in contour dynamics models of vortices subjected to forced planetary wave disturbances and thence to assess their significance for our understanding of stratospheric dynamics.