Simulation and analysis of inner-core vorticity mixing with a three-dimensional, nonhydrostatic mesoscale model

Building on recent work, we use a fully non-hydrostatic, mesoscale model (RAMS) to perform idealized simulations of instability and mixing in the cores of initially balanced, hurricane-like vortices. The azimuthal wind field and stratification of these vortices are closely modelled after observations of tropical cyclones. In particular, we simulate the growth of instabilities associated with the strong radial shears of the azimuthal wind field, and the ensuing vorticity mixing that results when these instabilities reach finite amplitude. Results show that at low levels, the instability mechanism is essentially barotropic, and that the disturbances spiral backwards with height due to the vertical shear in the eyewall region. As the essential features of these RAMS simulations are verified with both barotropic nondivergent and three-dimensional quasigeostrophic models, a universal paradigm of inner-core vorticity mixing begins to emerge