HR: 09:15h
AN: A31D-05    [Abstracts]
TI: The Tropical East Pacific as a Laboratory for Tropical Cyclones
AU: * Raymond, D J
EM: raymond@kestrel.nmt.edu
AF: Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801, United States
AB: The summertime tropical cyclogenesis rate per unit area in the eastern Pacific ocean is arguably higher than in any other location in the world. Many if not most of these cyclones form from African easterly waves which cross Central America into the Pacific. Of order 25% of these waves intensify into cyclones. A significant fraction of east Pacific tropical cyclones undergoes landfall on the Mexican coast. Those which do not, generally dissipate over cold ocean waters north of the east Pacific intertropical convergence zone, often not far from land. The layer of warm ocean water which supports the development of east Pacific cyclones is unusually shallow and is structured by anticyclonic vortices which form by various processes and propagate slowly to the west. These vortices locally deepen the oceanic mixed layer and support stronger convection than their surroundings, possibly promoting cyclogenesis and cyclone intensification. Cyclones in turn have an unusually large effect on the ocean mixed layer due to its shallowness. The east Pacific is thus a region of strong coupling between the atmosphere and the ocean, mediated in large part by the action of tropical cyclones. In most cases cyclogenesis, intensification, landfall, and decay over cold water occur within easy range of research aircraft launched from a number of Central American and Mexican bases such as San Jose, Huatulco, Acapulco, Puerto Vallarta, and Cabo San Lucas. The U. S. National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration, and the National Aeronautics and Space Administration have all successfully operated aircraft-based research projects from one or more of these locations. The frequency with which cyclones form, develop, and decay in the east Pacific and their proximity to land bases with excellent facilities make the tropical east Pacific an ideal international laboratory for the study of tropical cyclones. Given the importance of these cyclones to global weather and climate, every effort should be made to take advantage of this natural laboratory to enhance our knowledge of this phenomenon.
DE: 3307 Boundary layer processes
DE: 3329 Mesoscale meteorology
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly