Topographic Influence on African Easterly Wave Energetics and Convective Interactions

Mesoscale Convective Systems (MCSs) are a substantial source of the precipitation required for agriculture and human consumption in West Africa. Understanding the lifecycle behaviour of West African mesoscale storms poses unique challenges as these systems traverse strong thermodynamic gradients in their westward propagation from land to ocean. MCSs in this region are known to be associated with African Easterly Waves (AEWs). The topography of eastern Africa, namely the Ethiopian Highlands and Darfur Mountains have been shown to play an intricate role in the genesis of these waves through MCS initiation in that region. Topographic influences on the evolution and energetics of AEWs and the formation of MCSs within these AEWs are examined here. The Weather Research and Forecasting (WRF) model is employed to simulate the evolution over a 2-month period for three cases with varying topography: realistic, half-height, and no topography. An energetics analysis is done for 3 years to deduce the effect of the varying topography on the barotropic and baroclinic processes in the growth and maintenance of the AEWs.