Sensitivity of Tropical Cyclone Formation Rate to Genesis-Potential Parameters in Radiative-Convective Equilibrium.

Roughly 80 tropical cyclones form each year on Earth, but the reason for this number is still not well understood. Here, a series of idealized cloud-permitting simulations are performed on a doubly periodic f-plane to tease out the major rate-limiting factors that are commonly used in empirical genesis potential indices. Preliminary results reveal that tropical cyclogenisis occurs spontaneously between about 30-40 days, based on an initial set of simulations with fixed SST of 28°C, constant radiative cooling (-1.5 K/ day), and a realistic value of the Corliolis parameter (5x10-5 s-1). Sensitivity experiments are currently being conducted to test the how the ‘time to genesis’ varies with changes to the background rotation rate, potential intensity, radiative cooling, SST, vertical wind shear, and saturation deficit.