Extended Abstract (336K)1B.5
Case study of an intense African easterly wave
Gareth J. Berry, SUNY, Albany, NY
The evolution of a coherent African easterly wave that would later become Hurricane Alberto (2000) is examined using ECMWF operational analyses, METEOSAT and surface data. A conventional synoptic style view in addition to a potential vorticity view is adopted to explore the nature of this system.
Preliminary results show that the system is a complicated combination of isolated vortices with Rossby wave like structures. Evidence is presented which shows that the system is triggered in connection with mesoscale convection over Sudan. This convection initiates a westward propagating Rossby wave on the low level temperature gradient at the southern edge of the North African desert region, which interacts with diabatically generated vorticity over West Africa, resulting in the baroclinic growth of the system.
It also is suggested that the dynamics of the system were able to modify the nature of the convection. This results in further development of coherent structure such that upon crossing the West African coast, this system had already attained tropical depression status.
Session 1B, CONVECTION, waves, and precipitation I
Monday, 3 May 2004, 8:30 AM-10:15 AM, Napoleon I Room
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