Thursday, 13 February 2003
Waterspouts in the Tropics(and elsewhere!)
We show a series of spectacular photographs and field research highlights spanning 35 years, in tribute to the pioneering work by both Bob and Joanne Simpson on hurricanes and tropical convection, as well as Joanne's own work on waterspouts in GATE and over the Great Salt Lake. These results demonstrate anew the remarkable similarity of waterspouts and tornadoes, wherein the lower boundary is least important, but the near environment and parent cloud structure is all-important. Joanne's work showing the importance of prior in-cloud mesovortices and pre-existing boundaries in waterspout formation is illustrated. Finally, field studies of Florida Keys' waterspouts are used to show the likely 3D flow patterns and windspeed maxima in different portions of the waterspout vortex. About 10% of the Florida Keys and Tampa Bay waterspouts each year have peak velocities near the center of 50 m/sec or more. These data show that some waterspouts may approach F3 severity, and can inflict substantial damage to ships at sea, or coastal structures if they come ashore.