The Interplay of Tropical Convection, Moisture, and Vorticity (Invited Presentation)

This talk will review a long-term and influential theme of Dave Raymond’s research, the interplay of tropical convection, moisture, and vorticity. In a 2000 QJRMS paper, he hypothesized that over synoptic length and time scales, convective rainfall rate over most of the tropical oceans is primarily controlled by the mean saturation deficit of the atmosphere, rather than variations in the temperature profile. The 2001 EPIC field study, of which Dave was the lead scientist, provided observational evidence for this hypothesis from airborne radar and dropsondes, and suggested that wind-speed induced variations of surface latent heat flux explained half of the regional rainfall variability. Throughout Dave’s career, he had a passion for developing a better understanding of tropical cyclogenesis, and he wrote extensively on the evolution of mid-level and low-level vorticity in close connection with convection and moisture, as well nonlinear dynamical balance in the tropics. He also thought extensively about. His 2015 JAMES paper is an elegant summary marrying these threads into a sophisticated and powerful view of how tropical convection is coupled to synoptic scale dynamics.