Tropical cyclone climatology in a global warming climate as simulated in a 20km–mesh global atmospheric model

Possible changes in the tropical cyclones in a future, greenhouse-warmed climate are investigated using a 20km-mesh, high-resolution, global atmospheric model of MRI/JMA. Two types of 10-year climate experiments are conducted; the one is a present-day climate experiment, and the other is a greenhouse-warmed climate experiment with a forcing of higher sea surface temperature and increased greenhouse-gas concentration. A comparison of the experiments suggests that the tropical cyclone frequency in the warm-climate experiment is globally reduced by about 30% (but increased in the North Atlantic) compared to the presentday-climate experiment. Furthermore, the number of intense tropical cyclones increases. The maximum surface wind speed for the most intense tropical cyclone generally increases under the greenhouse-warmed condition (by 7.3 m s-1 in the Northern Hemisphere and by 3.3 m s-1 in the Southern Hemisphere). On average, these findings suggest the possibility of higher risks of more devastating tropical cyclones across the globe in a future greenhouse-warmed climate.