[A-CG33] 熱帯におけるマルチスケール大気海洋相互作用

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

*時長 宏樹¹、原 航太郎²、森 正人¹ (1.九州大学応用力学研究所、2.九州大学大学院総合理工学府)

キーワード：エルニーニョ、地球温暖化、熱帯低気圧

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.