A Study of the Energetics of African Easterly Waves Using a Regional Climate Model

TLDR: In this paper, the evolution and spatial distribution of the energetics of African waves are studied and complete eddy energy equations for an open system are derived for the computation of energy transformations during wave generation and dissipation.

Abstract: The evolution and spatial distribution of the energetics of African waves are studied. Complete eddy energy equations for an open system are derived for the computation of energy transformations during wave generation and dissipation. It is found that baroclinic overturning is the dominant energy source, although barotropic conversions can be almost equally important when there is concentrated moist convection south of the jet or shallow cumulus convection beneath the jet. The generation of active waves usually results from the nearly in-phase evolution of baroclinic and barotropic conversions, which are associated with significant rainfall over Africa. Significant barotropic instability associated with the horizontal shear is usually induced by concentrated deep convection on the southern flank of the jet. Barotropic conversions associated with the vertical wind shear may attain even greater magnitudes than that associated with the horizontal shear when shallow cumulus convection beneath the jet...