Energetics of idealized hurricane-like vortices

The energy flows in a core region of an idealized hurricane-like vortex are analyzed using energy equations derived in this study. The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model 5.3 (PSU/NCAR MM5V3) is used for the simulations. The vortex is initially axisymmetric with fixed surface conditions, such as an ocean with constant sea surface temperature 29C and f-plane valid at 17N. The simulations of the vortex are performed with calm environment (non-shear case) and with weak vertical shear (shear case). While the structure and intensity of the non-shear case are relatively steady, those of the shear case change dramatically with time. The energy flow analysis shows that the upper-level baroclinic eddy life cycles of the sheared vortex are mainly resplonsible for the weakening and structural changing of the shear case. Similar to a midlatitude baroclinic system, the baroclinic eddy life cycle in a hurricane-like vortex consists of eddy growth by a positive baroclinic process followed by eddy decaying by a negative barotropic process.