Buffering Effect of Atmosphere-Ocean Coupling on Intensity Changes of Tropical Cyclones Under a Changing Climate

The effect of atmosphere-ocean coupling on intensity changes of tropical cyclones (TCs) under global warming was examined using a regional high-resolution three-dimensional atmosphere-ocean coupled model. A storyline event attribution approach was applied to four historical intense TCs in the western North Pacific. The results indicate that atmosphere-ocean coupling buffers TC intensification as global warming progresses. This buffering effect increased as storms traveled northward. Moreover, the effect intensified as warming progressed, because reductions in sea surface temperature induced by the storm increased as the storm strengthened in future warmer climates. The magnitude of the buffering effect depended on the storm's size and translation speed; a large, slow-moving storm had significant resilience against global warming, whereas a compact, fast-moving storm was sensitive to global warming. A high-resolution atmosphere-ocean coupled model is important for more reliable future projections of TC intensity under the changing climate. Intense tropical cyclones (TCs) often cause extreme destruction. Therefore, to prevent future disasters, it is essential to understand how warmer environmental conditions will affect intense TCs. Atmosphere-ocean interaction during an intense TC can significantly reduce the sea surface temperature (SST). However, most projections of future TC intensity have been made either with a high-resolution atmosphere model that did not take account of atmosphere-ocean interaction or with a relatively coarse-resolution atmosphere-ocean coupled model that could not adequately reproduce intense TC intensity. We used a regional high-resolution three-dimensional atmosphere-ocean coupled model to quantitively assess how atmosphere-ocean coupling affected intensity changes of four historical intense typhoons under four different warming conditions. We found that the atmosphere-ocean coupling buffered changes in storm intensity associated with global warming by modulating the storm-induced SST-cooling in the vicinity of the storm center. We also found that the magnitude of the buffering effect depended on the storm size and translation speed and differed greatly among storms. Our results indicate that a high-resolution atmosphere-ocean coupled model that can represent storm intensity and size and the resultant SST-cooling should be used for reliable projections of future TC intensity under a changing climate. Intensity changes of tropical cyclones (TCs) under four different warming conditions are examined by a regional high-resolution atmosphere-ocean coupled modelAn atmosphere-ocean coupling effect buffers changes in storm intensity under a changing climateThe buffering effect intensifies as global warming progresses, because sea surface temperature-cooling induced by a TC increases as the TC strengthens