Variability of African easterly wave structures and behavior

Our perception of African easterly wave structures has been dominated by several composite studies. Based on these studies we know that AEWs typically have wavelengths of around 3000 km, peak amplitudes in dynamic fields close to the level of the AEJ (~700hPa) and near the surface baroclinic zone, and a peak rainfall signal close to or just ahead of the AEW-trough (in the West African region). While such information is very useful, and conceptual understanding has been gained from these studies, there is evidence that AEWs can vary substantially in terms of their structure and amplitude, their overall activity levels as well as in terms of the location of their genesis and track. Such variability can be important for influencing the weather experienced in the tropical North African region as well as the nature and probability of tropical cyclogenesis in the tropical Atlantic. This presentation will highlight the rich palette of African easterly wave structures and behavior that exists in the West African region and will include consideration of the different roles played by the environment, embedded convection and triggers for genesis.