An Examination of Quasi-balanced Dynamics in Hurricane Bonnie (1998) Using the Invertibility Principle of Ertel's Potential Vorticity

In this study, we examine the quasi-balanced dynamics of Hurricane Bonnie (1998) using the invertibility principle of Ertel's potential vorticity (PV). Given an atmospheric flow that is dynamically balanced, the conservative property of PV (in the absence of heating and friction) may be exploited to obtain a simple interpretation of all relevant dynamical information. Previous studies have shown that the invertibility approach is robust and represents reasonably well many typical features of axisymmetric hurricanes. In our study we will show that the invertibility approach is also useful for describing typical features present in the highly asymmetric case of Hurricane Bonnie (1998). In particular, the partial eyewall and double eyewall stages of Bonnie will be examined. With the aid of the NCAR/PSU mesoscale model (MM5) we will compare the " true " model field to the inverted quasi-balanced field to describe the quasi-balanced features in this highly asymmetric hurricane.