Future characteristics of African Easterly Wave tracks

African Easterly Waves (AEWs) impact Sahel rainfall and tropical cyclones (TCs). Gaining a detailed understanding of AEW behavior within global climate models can yield higher confidence in Sahel rainfall and TC projected trends. This study uses a Hovmöller tracking technique to track AEWs at 850 hPa in three reanalysis products and simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). AEW track characteristics are compared between reanalysis and CMIP5 historical simulations to establish historical biases. The resolution of the models is found to be more important in reducing biases in northern track AEWs compared to southern track AEWs, but large biases exist in the genesis and dissipation of AEWs over land and ocean. The tracking technique was then applied to future simulations (Representative Concentration Pathway 8.5). Between 1980–2000 and 2080–2100, models project an average increase of 1.5 AEWs (range of − 5.0 to + 7.6 AEWs) in the northern track, including an increased frequency of higher intensity waves. Projections of southern track AEWs are more varied compared to the northern track, with a projected model mean decrease of 1.1 AEWs but with a range of − 11.5 to + 11.6 AEWs in individual models. There is an indication of a shift in seasonality of southern track AEWs towards the later summer months, which may impact the timing of the Atlantic TC season. No clear differences were found in projected changes between models characterized as having high or low biases in the historical period.