[A-CG33] Multi-scale ocean-atmosphere interaction in the tropics

[ACG33-07] Future changes in tropical cyclone activity during the following summer-fall season of El Niño

*Hiroki Tokinaga¹, Kotaro Hara², Masato Mori¹ (1.Research Institute for Applied Mechanics, Kyushu University, 2.Interdisciplinary Graduate School of Engineering Sciences, Kyushu University)

Keywords:El Niño, Global warming, Tropical cyclone

Climate models in the Coupled Model Intercomparison Project phase 6 (CMIP6) predict a more frequent occurrence of extreme El Niño due to global warming. While increased extreme El Niño events strongly affect atmospheric convection over the tropical Indo-Pacific during boreal winter, their impact on future tropical cyclones in the following summer-to-fall season remains unclear due to insufficient model resolutions. Here we analyze the PRIMAVERA-CMIP6/HighResMIP multi-model ensemble simulations and show that the number of tropical cyclones over the western North Pacific is significantly reduced under global warming due to the increased extreme El Niño events. As in CMIP6 coarse resolution model simulations, most of the PRIMAVERA-HighResMIP models predict the future increase in extreme El Niño events under global warming. Extreme El Niños intensify the Indian Ocean capacitor effect on suppressed atmospheric convection over the tropical western North Pacific in the following summer to fall, significantly reducing the tropical cyclone occurrence there. In the presentation, we will also discuss the future changes in tropical cyclone activity over the other tropical regions.