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. In this study, we examine the projection of future changes in summertime stationary waves and explore the implications for TC activity. Most 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 activity over the Central Pacific and a potential decrease over the North 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 biases in the spatial distribution of TC activity and calls for caution when utilizing climate models to explicitly project future TCs. The inter-model spread in the projected changes in TUTTs is also investigated.