29th Conference on Hurricanes and Tropical Meteorology


Easterly wave structural evolution over West Africa and the East Atlantic

Matthew A. Janiga, SUNY at Albany, Albany, NY

African easterly wave (AEW) tracks were produced by tracking coherent synoptic-scale vorticity maxima at 700 hPa over the period July through September, 1989-2005. The structural evolution of easterly waves over West Africa and the East Atlantic is investigated by examining the composite evolution of long-lived AEWs.

Attention is paid to the evolution of the low-level flow associated with baroclinic growth processes. Over land the mid-level vorticity maxima being tracked induce temperature perturbations along the surface baroclinic zone in the Sahel. The warm (cool) temperature perturbations to the baroclinic zone result in more cyclonic (anti-cyclonic) low-level flow. Over Africa the baroclinic aspects of AEW structure play an important role in modulating low-level moisture and deep moist convection. As the AEW moves westward into the East Atlantic the relative importance of the southern mid-level vortex increases. This is associated with the cessation of baroclinic development beyond the coast of West Africa.

extended abstract  Extended Abstract (2.3M)

wrf recordingRecorded presentation

Session 5D, African Climate and Weather I
Tuesday, 11 May 2010, 8:00 AM-9:45 AM, Tucson Salon A-C

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