Future Projection of Summertime Subtropical Stationary Waves and Implications for Tropical Cyclone Activity

Summertime stationary waves offer a unified framework that integrates the impacts of tropical and extratropical processes on tropical cyclone (TC) activity. This framework provides a comprehensive hemispheric perspective, facilitating our understanding of the variability and predictability of TC activity over the North Atlantic and North Pacific. In this study, we apply this framework to the projection of future TC activity. The projections of CMIP6 models suggest a reduction in the extent of the Pacific Tropical Upper Tropospheric Trough (TUTT) and an increase in the Atlantic TUTT. These changes imply a potential increase in TC risk over the Central Pacific and a potential decrease over the tropical Atlantic. Further analysis reveals that the observed anticorrelation between Accumulated Cyclone Energy (ACE) and TUTT at the basin scale is poorly represented by most HighResMIP models. This model deficiency likely stems from model biases in the spatial distribution of TC activity and calls for caution when utilizing climate models to explicitly project future TCs.