Effects of surface fluxes on the moist potential vorticity distribution in the axisymmetric tropical cyclone boundary layer

Abstract

This study investigates the structure and dynamics of simulated tropical cyclone boundary layers (TCBLs) using a moist potential vorticity () framework. in the boundary layer of tropical cyclones is related to the distribution of equivalent potential temperature () and absolute angular momentum (), and can therefore respond to air–sea transfers of moist entropy and momentum. We examine the distribution of using axisymmetric simulations of tropical cyclones and study the effects of changing both surface entropy and surface momentum fluxes on the distribution. The simulated TCBL is characterized uniquely as a region of negative with a robust and coherent layer of high‐magnitude , extending from the surface in the inner core to the top of the TCBL in the outer core. This layer is referred to as the potential vorticity minimum layer (PVML). Detailed budget analyses indicate that both diabatic heating of and frictional dissipation contribute to the generation of large negative in the inner core. On the other hand, diabatic heating is the primary mechanism responsible for the maintenance of the PVML in the outer core, with friction playing a smaller indirect role.