Exploring the Variability of African Easterly Wave Activity Across Seasons

African Easterly Waves (AEWs) are the primary initial disturbance that precede the majority of tropical cyclone (TC) development in the Atlantic basin. They are also important drivers of precipitation in northern Africa. However, questions remain about the interseasonal variability of AEWs and its potential impact on TC activity. In this work, AEWs and their attributes are objectively tracked and composited using two reanalysis datasets. AEW seasons are grouped by outcome, such as TC activity, and the phasing of large-scale climate oscillations, like the El Niño – Southern Oscillation (ENSO). This allows the characteristics of AEWs and the background environment to be compared across groupings of seasons. As expected, the average strength of AEWs over the eastern Atlantic is significantly higher in years with elevated TC activity. However, we also find a statistically significant relationship between ENSO and AEW strength. AEWs tend to be stronger during La Niña years, both over the eastern Atlantic and the African continent. The observed seasonal differences in AEW strength appear to be related to variations in the position and strength of the African Easterly Jet (AEJ). These findings expand our understanding of the relationship between ENSO and seasonal AEW behavior in the Atlantic. Furthermore, they also illuminate another potential teleconnection between ENSO and TC activity, especially given the established relationship between AEW strength and downstream TC development.