Mesoscale dynamics of tropical cyclogenesis observed during PREDICT

The Pre-Depression Investigation of Cloud-systems in the Tropics (PREDICT) field campaign was conducted during the summer of 2010 to explore the multi-scale dynamic and thermodynamic interactions that lead to tropical cyclogenesis. Recent studies have indicated that a protected, quasi-closed recirculation region inside a parent synoptic scale disturbance provides a favorable environment for tropical development. Results from the TPARC/TCS08 and the PREDICT experiments suggest that the existence of a relatively deep and strong recirculation region on the meso-alpha scale, or “pouch”, is a very favorable condition for tropical cyclogenesis. At the smaller scales, aggregation of convectively amplified cyclonic vorticity in the lower troposphere has been suggested to be the primary upscale growth mechanism for the emergent tropical cyclone. This talk will present preliminary analyses on the multi-scale processes spanning the meso-alpha scale recirculation region and rotating deep convection on the meso-gamma scale. Doppler radar data collected as part of the complementary NOAA IFEX experiment will be used to document the convection during the development of Hurricane Karl. These radar analyses will be presented in the context of the data collected by the NSF/NCAR G-V on the meso-alpha scale. To test the universality of the mesoscale processes leading to cyclogenesis, the results will be compared with Doppler radar analyses from the recent TPARC/TCS08 field campaign in the Western Pacific.