| The high frequency of cyclogenesis in the northwestern Gulf of Mexico is often attributed to warm sea surface temperature. In this thesis, the importance of surface fluxes were documented to understand the air-sea interaction effect on the cyclogenesis and storm intensification by using a coupled ocean-atmosphere model of the extratropical 1993 SuperStorm (12-14 March 1993). This storm, also known as the "Storm of the Century," had a wide-reaching effect on the Northern Gulf of Mexico region and the East Coast of the United States.;In this study, the ocean response and its effects on the storm and upper level troughs and precipitation were examined using the Gulf of Mexico Regional Coupled Modeling System (GoM-CRMS). GoM-CRMS incorporates two-way coupling between the atmospheric model (Weather Research & Forecasting Model, WRF) and the ocean model (Regional Ocean Modeling System, ROMS). The WRF horizontal resolutions studies are 15 km, 5 km, or ~1.7 km resolutions respectively and the ROMS horizontal resolution is 8 km.;Comparisons between Climate Forecast System Reanalysis (CFSR) data, observations and simulations showed that the simulations, especially finer atmospheric resolution simulations, were in better agreement with the observations, root mean square differences (RMSD) between observation and simulations for mean sea level pressure (MSLP), 2-meter air temperature, and wind speed values were ranging between 1 to 4.5 mb, 1.4 to 5.7 ms-1 and 1.2 to 7.2 °C, respectively. Storm tracks for each simulation compared well to the reference storm track extracted from the North American Surface Analysis. Simulations also showed that the latent heat flux is affected by model domain resolution and sea surface temperature temporal resolution. The 500 mb relative vorticity and geopotential height analysis of GoM-CRMS simulation illustrate the shortwave troughs which is leading the storm to intensify and 6 hours accumulated precipitations amount maps that showed the precipitation area located over the downstream of the trough were similar compared to CFSR representation, and were largely insensitive to the SST forcing and model resolution. Therefore, the changes in surface characteristics are largely driven by the differences in resolution and SST coupling, rather than changes aloft. |
