Mechanisms of African Easterly Wave Genesis

African easterly waves (AEWs) are warm season synoptic scale disturbances that propagate across western Africa and often influence regional convective systems or develop into tropical cyclones after they reach the Atlantic Ocean. For decades, the paradigm for AEW genesis was the mixed baroclinic-barotropic instability of the African easterly jet, but recent studies have indicated that baroclinic and barotropic conversions from these instabilities alone do not account for observed AEW growth rates. More recently, both triggering by mesoscale convection and upstream development by previous AEWs have emerged as genesis mechanisms. In this study, we examine both genesis mechanisms to examine their validity as well as the variability of AEW development in relation to them. We use the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) and satellite derived products to determine how often each genesis mechanism can be attributed AEW initiation and how differing magnitudes or scales of either mechanism impact AEW development.