How Small-Scale Turbulence Sets the Amplitude and Structure of Tropical Cyclones

Tropical cyclones are intense vortices whose interior dynamics are quasi-balanced and as such can be described by potential vorticity conservation and invertibility. As with most tropical phenomena, moist convection establishes a nearly neutral state which is equivalent to one of vanishing saturation potential vorticity in the interior. This in turn implies that, as with Eady models of baroclinic atmospheres, the interesting physics occurs at the boundaries. It is well known that turbulent fluxes of enthalpy and momentum from the ocean ultimately control the intensity of TCs, but the role of the upper boundary condition has not been thoroughly explored. In this talk I will argue that small scale turbulence in the outflow layer has a strong influence on both the intensity and structure of tropical cyclones, and show that accounting for the effects of such turbulence yields analytic expressions for both the structure and time evolution of these storms.