LAUSR

The high-resolution, three-dimensional, life-cycle simulation described in Part I is used to explore further aspects of tropical cyclone spin up and early maturity in the framework of the rotating-convection paradigm. Unbalanced and non-axisymmetric processes are a prominent feature of the spin up process. The analyses reveal a reservoir of air with high equivalent potential temperature in the low-level eye region and indicate the importance of this reservoir in supporting convective instability necessary for vortex spin up. The analyses show also that the ability of inflowing air to access this reservoir is linked to the symmetric and asymmetric boundary layer dynamics of the vortex. Analyses of the radial force field provide an improved understanding of the process of spin up within the boundary layer and eyewall. They provide also an explanation for inflow jets sandwiching the upper tropospheric outflow layer that are frequently found in numerical model simulations. Overall, the results point to the significant limitations of a purely axisymmetric and/or balance description of tropical cyclone dynamics.