On the role of SST and Upper Ocean Thermal Structure on Rapid Intensification and Maximum Intensity in Tropical Cyclones.

This study investigates the Rapid Intensification (RI) and Maximum Intensity (MI) of Hurricanes Wilma and Rita (2005), focusing on the impact of Sea Surface Temperature (SST), SST anomalies (SSTA), Ocean Heat Content (OHC) and the Ocean Mixed Layer Depth (OMLD). Utilizing numerical model simulations, the research aims to quantify the ocean's impact on tropical cyclone intensity, particularly under different OHC scenarios. Numerical simulations are performed using the Weather Research and Forecasting (WRF) model coupled with a simplified 1D Ocean Model. Simulations performed include a control with initialization consistent with observations, removing the SSTA, modulating the OMLD (doubling and halving), and modulating SST initialization fields at –3, –2, –1, +1, +2, +3 Celsius. Simulations successfully reproduce the RI phase and intensity trajectory of Hurricane Wilma and Rita, with the SSTA significantly impacting both intensity and track. Preliminary results (under ideal atmospheric conditions) indicate the SSTA produces an average 27% lower Central Sea Level Pressure (CSLP), a 30% difference in minimum CSLP, and a mean difference in maximum wind speed of approximately 6%. Additionally, SSTA enhances the deepening rate during the RI phase by about 47%, increases the total surface heat flux by approximately 19%, and produces a 10% increase in accumulated grid scale precipitation.