Tropical cyclogenesis and mid-level vorticity

This paper reviews and summarises our work on the thermodynamics and vorticity dynamics of tropical cyclogenesis with special emphasis on the use of observations from two recent field programs, T-PARC/TCS08 (THORPEX Asian Regional Campaign/Tropical Cyclone Structure experiment) and PREDICT (PREDepression Investigation of Cloud systems in the Tropics). Dropsondes deployed from high altitude plus airborne Doppler radar data (in T-PARC/TCS08) allowed examination of candidates for tropical cyclogenesis in unprecedented detail. The subtle interplay of dynamics and thermodynamics and, in particular, the role of the mid-level vortex in enabling spin up of a surface cyclone are elucidated. The interplay between this process and other investigators' ideas about cyclogenesis is examined also. Finally, those areas of cyclogenesis needing further work are enumerated.