Radial mixing of heat, momentum, and potential vorticity between the hurricane eye and eyewall has received recent attention as an important internal factor governing intensity change. Some physical examples are mixing of air with high moist entropy from the eye to the eyewall by eye mesovortices and quasi-barotropic breakdown of the eyewall potential vorticity ring. Like other atmospheric flows, the hurricane inner-core likely has distinct partial barrier (trajectories are integrable) and mixing (chaotic advection) regions. Understanding the location and effectiveness of these regions is paramount for a complete understanding of the internal dynamics of hurricane intensity change.

As a first step toward quantifying these ideas, the effective diffusivity diagnostic tool is applied to some simple barotropic hurricane-like vortices. First, existing theory is specified for the case of a barotropic vortex. Then, the diagnostic tool is applied to the output of simulations of unforced unstable hurricane-like vortices with a nondivergent barotropic model.