Forced, balanced model of tropical cyclone intensification

A simplified, axisymmetric, one-layer model of tropical cyclone intensification is presented. The model is based on the Salmon wave-vortex approximation, which can describe flows with high Rossby number and low Froude number. After introducing an additional approximation designed to filter propagating inertia-gravity waves, the problem is reduced to the prediction of potential vorticity (PV) and the inversion of this PV to obtain the balanced wind and mass fields. The PV prediction/inversion problem is solved analytically for forcing in a two-region, three-region, and multi-region configuration. The two-region model provides insight into tropical cyclone incubation times before rapid intensification. The three-region model illustrates how hollow PV structures form. The multi-region model demonstrates the inward movement of angular momentum surfaces across the radius of maximum wind. The development of tropical cyclones in total energy/maximum velocity diagrams will also be discussed for the three models to compare vortices of varying size and intensity.