日本地球惑星科学連合2023年大会

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[E] 口頭発表

セッション記号 A (大気水圏科学) » A-AS 大気科学・気象学・大気環境

[A-AS04] 台風研究の新展開~過去・現在・未来

2023年5月23日(火) 10:45 〜 12:00 103 (幕張メッセ国際会議場)

コンビーナ:辻野 智紀(気象研究所)、金田 幸恵(名古屋大学宇宙地球環境研究所)、伊藤 耕介(琉球大学)、宮本 佳明(慶應義塾大学 環境情報学部)、座長:辻野 智紀(気象研究所)、金田 幸恵(名古屋大学宇宙地球環境研究所)

11:30 〜 11:45

[AAS04-09] Cause of the Recent Tendency of Tropical Cyclones Approaching Coasts as Revealed by HighResMIP-PRIMAVERA Simulations

*小川 史明1見延 庄士郎1、Malcolm J. Roberts2、Haarsma Rein3、Putrasahan Dian4、Roberts Christopher D.5、Scoccimarro Enrico6、Terray Laurent7、Vidale Pier Luigi8 (1.北海道大学大学院理学研究院、2.英国気象局ハドレーセンター、3.オランダ王立気象研究所、4.マックスプランク気象研究所、5.ヨーロッパ中期気象予報センター、6.欧州地中海気候変化研究所、7.ヨーロッパ先端科学計算研究所、8.レディング大学気象研究科)

キーワード:熱帯低気圧、人為起源の強制、自然変動、PRIMAVERA

Tropical cyclones developing over the ocean threaten society when they approach land. A recent study found a tendency for tropical cyclones to reach their maximum intensity closer to the coast over the last 40 years. However, whether this trend is due to global warming or natural variability is unclear.

This study aims to identify the cause of the observed trend. To this end, we analyzed the output of a high-resolution global multi-model ensemble prepared by the PRIMAVERA project according to the CMIP6 HighResMIP protocol. We assume that the atmosphere-only simulations reproduce both the responses to anthropogenic forcing and natural climate variability constrained by sea-surface temperature (SST) and that the air-sea coupled simulations reproduce only the forced response although other factors such as SST biases/errors may influence the results. The results show that the atmosphere-only simulations reproduced the observed trend, but the atmosphere-ocean coupled simulations did not. This suggests that the observed trend is not caused by global warming but by natural variability. We find that the relevant natural variability is the Inter-decadal Pacific Oscillation (IPO). A significant contribution to the trend is the variation of tropical cyclone genesis locations associated with IPO in the models, consistent with the results of observation data.