The Mean Characteristics of African Easterly Waves Coupled to Saharan Mineral Dust Aerosols

Over North Africa during the summertime, African easterly waves (AEWs) regularly interact with the vast amount of Saharan mineral dust (SMD) aerosols emitted from the desert surface. In this study, we use the NASA Modern-Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero) to examine the mean characteristics of AEWs that are coupled to synoptic-scale SMD plumes. To isolate the AEWs associated with SMD plumes of synoptic-scale, the dynamical and dust fields from MERRAero (wind, temperature, vorticity, dust mixing ratio, AOD, etc.) are projected onto the 2-6 day time-filtered AOD over the Sahara Desert by using lag regression techniques. The regression, which uses the reanalysis fields from the summers of 2003-2013, provides several characteristics of the SMD-coupled AEWs, including their three-dimensional structure, phase speed, wavelength, and energetics. By examining the SMD-coupled AEWs, several questions arise, including: What is the synoptic variability of the SMD plumes over North Africa and the Eastern Atlantic Ocean? How do AEWs contribute to the mobilization and transport of SMD? What are the phase relationships between the AEWs and the synoptic-scale SMD plumes, and how do the phases change during their evolution? Answering these questions, and others, will aid in understanding the complex interactions that exist between AEWs and synoptic-scale SMD plumes.