Recorded presentation3A.3
A 3-4 day Convective Oscillation between East Africa and Equatorial Congo during Boreal Summer
Chris D. Thorncroft, University at Albany, SUNY, Albany, NY; and A. Mekonnen
Spectral analysis using long-term brightness temperature data highlights the presence of pronounced and significant 3-4 day periodicity in convection over central Sudan and adjacent western Ethiopia during the boreal summer season, a region not well known for synoptic scale wave activity. Composite analysis using a lag regression technique indicates that much of this variability arises in association with a regional oscillation that takes place between East Africa and the equatorial Congo region. The mechanism to explain this marked oscillation involves two key processes: (i) A local convective recharge-discharge process associated with periods of increasing conditional instability (charging) and decreasing conditional instability (discharging) and (ii) A dynamic interaction between the two regions associated with low-level moisture transport. A conceptual model will be presented to illustrate these processes and the consequences of this oscillation for the regional climate and climate variability will be discussed. Recorded presentation
Session 3A, African Climate: III. Convection and Synoptic Systems
Monday, 21 January 2008, 1:30 PM-2:30 PM, 215-216
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