On the Relationship between the African Easterly Jet–African Easterly Wave System, Saharan Mineral Dust Aerosols, and West African Precipitation (Invited Presentation)

The African easterly jet (AEJ)-African easterly wave (AEW) system is a key feature of the summertime circulation over North Africa. In this study, we examine the relationship between Saharan mineral dust (SMD) aerosols, West African precipitation (WAP), and the AEJ-AEW system for the twenty-year period spanning 1998-2017. We use three reanalysis datasets: (1) MERRA-2 for aerosol optical depth; (2) TMPA for accumulated rainfall; and (3) ECMWF for the wind and temperature fields. July-September averages are calculated for each field and for each year. Years with above or below average dust and precipitation amounts are compared to determine the relationship between SMD, WAP, and the inter-annual variability of the AEJ-AEW system. To examine the inter-annual variability of the AEJ-AEW system, we calculate the baroclinic and barotropic energy conversions, eddy kinetic energy, and diabatic generation of eddy available potential energy. The energetics analysis reveals a strong connection between SMD, WAP, and the structure and strength of both the AEJ and AEWs. Initial results show in years with above average SMD, the shear of the AEJ and the energy conversions are stronger.