Extratropical Impacts on Tropical Cyclone Activity: A Global Perspective

Our recent studies revealed the impacts of extratropical Rossby wave breaking (RWB) on Atlantic tropical cyclones (TCs). When RWB occurs more frequently over the North Atlantic, the enhanced mixing between the warm, moist air from the tropics and the cold, dry air from the extratropics results in strong vertical wind shear and reduced tropospheric humidity in the Atlantic main development region (MDR); the basin-wide TC counts are reduced, and TCs are generally less intense, have a shorter lifetime, and are less likely to make landfalls. The impacts of extratropical Rossby wave breaking on tropical cyclone activity is examined over the western North Pacific and the eastern North Pacific in this study, and a global perspective of the extratropical impacts on tropical cyclone activity is proposed based on the analysis.