[A-CG30] 中緯度大気海洋相互作用

[ACG30-P06] Future changes of tropical cyclone-induced precipitation distribution around Kyushu Islands in dynamically downscaled large-ensemble simulations

山口 修平¹、*望月 崇¹、川村 隆一¹、川野 哲也¹ (1.九州大学大学院理学研究院)

キーワード：地球温暖化、熱帯低気圧、力学的ダウンスケーリング

By using a large-ensemble set of 5-km resolution (SI-CAT DDS5TK) simulations dynamically downscaled from 20-km resolution (d4PDF-RCM) simulations, we define statistical changes in precipitation distribution around Kyushu Island associated with tropical cyclone attacks in future. The d4PDF-RCM represents the enhancement in intensity and decrease of the numbers of the tropical cyclone over the Northwesten Pacific. The precipitation amount is increased near the center of the individual tropical cyclone. In contrast, the SI-CAT DDS5TK can represent detailed spatial patterns of rainfall changes rather than uniform increase, particularly due to potential influences of the finer-resolved topography. When focusing on the east coast of Kyushu Island where the tropical cyclone attack is a major factor to control the rainfall changes in future, the tropical cyclone works to reduce the rainfall through the southward shift of the moisture flux convergence. The rainfall is enhanced at the sea surface of the southeast of the Kyushu Island, probably because the tropical cyclone moves more slowly, its lifetime becomes longer and hence a chance of attack of relatively weak cyclones can be increased in the extratropical area.