Variability of the African Easterly Jet and Its Influence on Easterly Waves

The African Easterly Jet (AEJ) is believed to be one of the phenomena driving regional as well as global atmospheric circulation. Specifically, within the Sahel region, the AEJ and African Eastern Waves (AEWs) are important features associated with the West African Monsoon.  Both features determine weather patterns and storm generation in this region. The goal of this study is to identify distinct cases of the AEJ structure and investigate how it affects the AEW formation. Current studies have shown that the AEJ possesses a double-core structure during the month of August when the jet is the strongest, which impacts local climatic conditions in the Sahel as well as influence the formation of AEWs. For this study, we obtained zonal and meridional wind data measured at 850 hPa and 600 hPa during the month of August from 1948 to 2016. Plots of the monthly mean of zonal wind were created and the years where the double core was apparent were chosen for further analysis. The years showing the double core structure were used to construct Hövmoller diagrams of the meridional wind in order to determine AEW track and lifespan. Preliminary results identified distinct cases where the structure of the AEJ deviated from its mean structure, including the western (eastern) core being located north relative to the eastern (western) core. Comparisons of the different cases can provide valuable insight about the relationship between the AEJ, easterly waves and rainfall variability over the Sahel as well as tropical cyclogenesis at the West African coast.