Characteristics and structures of precipitation associated with tropical cyclone intensity changes

Previous studies establish an empirical relationship between intense precipitation in the eyewall and tropical cyclones' (TCs) wind intensification. It is also found that surface rain rate aligns with the TC formations and intensity changes. In this study we further investigate the relationship between characteristics of TC surface precipitation and TC intensity changes.

Major tropical cyclones over the Western Pacific during August and October of last ten years are chosen in this study. Using a multi-sensor precipitation product from NASA's Tropical Rainfall Measuring Mission (TRMM) and the best track data from the Joint Typhoon Warning Center (JTWC), the relationship between the surface precipitation and TC intensity is examined at different phases of TC life cycles. A wave filter method is applied to the time series of the maximum and averaged precipitation. To explore the role of intense convection on the rapid intensification of TC and the relationship between intense convection and surface precipitation, airborne radar data (ELDORA) from THORPEX Pacific Asian Regional Campaign/Tropical Cyclone Structure-08 (T-PARC/TCS08) field program are also used to demonstrate the vertical structures of TC eyewall for selected cases.

Preliminary results show relationships between TC intensity changes and intense precipitation (>= 40 mm/hr) during various phases of TC life cycle. More detailed analysis and results will be presented in the conference.