Role of the Atlantic Warm Pool on the Development of Category-Five Hurricanes

The recent increase in the number of tropical cyclones (TCs) developing in the Atlantic basin has prompted the need for a better understanding of the factors controlling TC frequency. The Atlantic Warm Pool (AWP) is known to impact a hurricane's trajectory by shifting the origin of the storms eastward, and thus reducing the probability of landfall in the United States. However, it is still unclear if and how the AWP might affect hurricane intensification. Therefore, in this research, the potential role of the AWP on hurricane intensification is investigated. Although the effects of high sea surface temperatures are known, this study goes beyond surface temperature profiles and focuses on the possible significance of the depth and heat content of the AWP on the intensification of TCs. For this research, statistical methods were applied on the Simple Ocean Data Assimilation (SODA) 2.2.6 reanalysis and HURDAT data sets from 1971 through 2008. All category five hurricanes that originated or developed within the AWP boundary during this 37 year period were identified. Their trajectories were plotted against the monthly oceanic heat content (OHC) above 100 meters, to observe the behavior of each individual storm as it passed through areas of high or low OHC. Results indicated that more than 90% of the category five storms that developed in the AWP region, intensified in areas of high heat content. Although other atmospheric variables have to be taken into account, these preliminary results suggest that a high OHC in the AWP area may be a necessary condition for a TC to develop into a category five hurricane, indicating that subsurface temperature profiles may be useful as predictors when forecasting the intensity of a TC.