Assessing the Rapid Weakening of Tropical Cyclones with Infrared and Microwave Satellite Imagery

Improvements in predictions of tropical cyclone intensity change continue to lag behind improvements in forecasting tropical cyclone motion, and rapid intensity changes negatively affect these errors. Efforts have been made to improve prediction of rapid intensification (a 30 kt intensity increase in 24 h) of tropical cyclones, but little work has been done to improve prediction of rapid weakening (a 30 kt intensity decrease in 24 h).

Research using remotely sensed microwave data has shown promise in predicting rapid intensification events by highlighting increased organization in the tropical cyclone's inner core. As microwave data reveal more information about the structure of a tropical cyclone than can be gleaned from visible or infrared satellite imagery alone, their utility in assessing rapid weakening events should be explored. In this study, the Hurricane Satellite (HURSAT) dataset will be utilized to investigate structural changes during North Atlantic and eastern North Pacific rapid weakening events in both infrared and microwave imagery during the period 1987-2009. Patterns associated with rapid weakening will be evaluated and compared with slower weakening events for forecast applicability.