Future projection of the African easterly waves in a high-resolution atmospheric general circulation model

Abstract Simulating the features of the African Easterly Waves (AEWs), such as their westward propagation off the coast, is challenging for coarseresolution climate models. In this study, we use High-Resolution Atmospheric Model (HiRAM) to simulate AEWs and analyze their future projections by the end of the 21 st century. The simulations are performed globally at a horizontal resolution of ∼ 25km. The model uses shallow convective parameterization for moist convection and stratiform cloudiness. Future projections are conducted using representative concentration pathway 8.5. The AEWs are separated with respect to their periods as 3–5- and 6–9-day AEWs, and bandpass filtering is used to filter the waves from the mean flow. HiRAM simulates structure and propagation of the waves well; however, it tends to overestimate the associated precipitation. In the future, the AEW activity and intensity of the circulation will considerably increase. The northward extent of the AEW track also shows a significant increase in the future. The increased wave activity can be translated as more Atlantic hurricanes in the future because AEWs are the seed disturbances for cyclogenesis in this region.