Satellite Microwave Detected SST Anomalies and Hurricane Intensification

The year 2005 is a record-breaking year for Atlantic Hurricanes. There were 28 named storms and 15 hurricanes, including three Category 5 hurricanes, Katrina, Rita, and the strongest hurricane on record, Wilma. Katrina became the costliest and one of the deadliest hurricanes in the US history. Better understanding and prediction of hurricanes will allow societies to be better prepared to minimize life and property damages. SST data from remotely sensed infrared measurements, like GOES, AVHRR, and MODIS, show missing values over the cloudy regions associated with hurricanes. While satellite microwave measurements, like the Tropical Rainfall Measuring Mission (TRMM) microwave imager (TMI), can provide SST even under cloudy conditions. Both satellite measurements and buoy observations show that SST increases in advance of significant hurricane intensification. This is probably because it may need a period of time for a tropical cyclone to accumulate energy to develop into a hurricane. Moreover, hurricane intensification may also be related to the actual location of high SST. Our results indicate pre-existing high SST anomaly (SSTA) located at the right side of the storm track for Hurricane Katrina. Numerical simulations of three control experiments also confirm the importance of the relative positioning of SSTA with respect to the storm track. Similar situations are also found for Hurricanes Rita and Wilma. On the contrary, if there is no high SSTA at the right location, a hurricane may not be able to undergo further intensification. This may explain why not all tropical cyclones associated with warm waters can attain peak intensity (categories 4 and 5) during their life cycle. Using this finding, during this year, in advance of several days, we successfully predicted tropical storm Ernesto could not have developed into a hurricane again after it entered the ocean since its first landfall in Cuba.