The Influence of ENSO on African Easterly Waves and Tropical Cyclogenesis

Previous studies show that El Niño-Southern Oscillation (ENSO) can influence the vertical wind shear in the western Atlantic basin, and therefore can both suppress and enhance tropical cyclone intensification in this region. During El Niño periods, enhanced wind shear tends to weaken tropical cyclones, whereas during La Niña periods, weakened wind shear tends to strengthen tropical cyclones. These are understood effects on developed tropical storms and hurricanes. However, the effects of ENSO on the behavior of African Easterly Waves (AEWs) and their potential for tropical cyclogenesis is not as well-established. The ECMWF ERA5 reanalysis dataset is used to analyze the strengths of AEWs via tracked vorticity maxima, coupled with their environmental wind shear and humidity. Results will be presented for different regions of the Atlantic basin during El Niño and La Niña phases.