UC Berkeley

Abstract The deadly and destructive nature of tropical cyclones (TCs) makes understanding their response to future climate change of the utmost importance. TC genesis hinges on multiple factors, including an initial disturbance. African easterly waves (AEWs) have been shown to serve as such disturbances for TCs developing in the North Atlantic. It is therefore crucial to understand the relationship between AEWs and TCs and how this relationship may be affected by climate change. In this study, we examine the AEW‐TC relationship in historical and future climates using three models from the HighResMIP PRIMAVERA simulations. The AEWs and TCs were tracked in the model data using objective tracking algorithms, and AEW and TC tracks were then matched together if they were close to each other in space and time. The strength of the AEWs was measured using the eddy kinetic energy and the curvature vorticity of the waves. TC strength and intensity were measured using potential intensity and lifetime maximum 10 m windspeed. We found that future changes in the frequency of AEWs are not a good indicator of future TC activity. However, AEW strength, as well as environmental conditions conducive to strong TCs, are good indicators of AEWs that develop into TCs in both historical and future climates. Plain Language Summary Tropical cyclones (TCs) are both deadly and destructive and it is important to understand how they will respond to future climate change. African easterly waves (AEWs) are disturbances that can develop into TCs that form in the North Atlantic. The relationship between AEWs and TCs is an important part of understanding how TCs will be affected by climate change. In this study, we examine the AEW‐TC relationship in historical and future climates using three climate models. AEWs and TCs were tracked in the model data, and AEW and TC tracks were then matched together if they were close to each other in space and time. The number of AEWs and TCs in the historical and future climates were compared. We found that future changes in the number of AEWs are not a good indicator of future changes in the number of TCs. However, AEW strength, as well as environmental conditions conducive to strong TCs, are good indicators of AEWs that develop into TCs in both historical and future climates. Key Points Future changes in the frequency of African easterly waves (AEWs) are not a good indicator of future tropical cyclone (TC) activity AEWs that develop into TCs are stronger than non‐developing waves in historical and future climates Wave strength combined with environmental conditions are good indicators of tropical cyclogenesis from waves