Investigating The Origin of African Easterly Waves

Monday, 18 April 2016: 10:45 AM
Miramar 1 & 2 (The Condado Hilton Plaza)
Joshua Dylan White, North Carolina State Univ., Raleigh, NC

African easterly waves (AEWs) are synoptic-scale disturbances that modulate west African precipitation and are precursors of a majority of Atlantic hurricanes. For decades, the proposed mechanism for generation of AEWs was the combined baroclinic-barotropic instability of the African easterly Jet (AEJ). Recent studies have revisited this issue, and two alternative mechanisms for AEW origin have emerged: (1) Triggering by mesoscale convection; and (2) Upstream energy dispersion in AEW wave packets. Our goal is to rigorously test these two mechanisms. In this study, we examine one season (July-October, 2006) in detail to determine whether clear evidence of convective triggering and/or upstream energy dispersion for each AEW can be discerned. We use European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) and satellite derived products to monitor wave activity and active convection. An eddy kinetic energy (EKE) budget will demonstrate contributions to AEW development from baroclinic and barotropic conversions, and upstream energy dispersion. Analysis of convection (size, duration and location) and its upscale impact will aid in determining its role AEW origin.
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