Linear Motion of a Two-Layer, Baroclinic Hurricane in Shear

For appropriate ranges of model stratification and initial vortex structure, an imposed environmental shear results in the separation of initially coincident upper and lower vortices and their subsequent rotation about each other in loops that converge to equilibrium solutions. At equilibrium, the two vortices propagate with constant separation of the order of a few hundred meters, even with extreme shear of 100 m/s. The structure of these vortices has been examined and they are found to be like those reported by S. Jones (1995) for a fully nonlinear gridpoint model. The structure of the restoring force is also shown.