2022 Fiscal Year Final Research Report
Potential contribution of interbasin interaction to the western Pacific climate variability and tropical cyclone activity on subdecadal to decadal timescales
| Project/Area Number |
17K05661
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | Kyushu University (2019-2022)
Japan Agency for Marine-Earth Science and Technology (2017-2018) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
森 正人 九州大学, 応用力学研究所, 助教 (00749179)
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| Project Period (FY) |
2017-04-01 – 2023-03-31
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| Keywords | 気候モデリング / 十年規模変動 / 中長期変調 / 部分同化実験 / データ同化 / 地球温暖化 / 気候予測 / 熱帯低気圧 |
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| Outline of Final Research Achievements |
We tried to enhance our knowledge of decadal variations in the western Pacific climate and tropical cyclone activity, focusing on interbasin interactions in the climate system. We have found a subdecadal variation that has been distinctively observed in the 2000s over the tropical Pacific, possibly related to the potential chance of heavy rainfall near Japan. By performing partial data assimilation of a global climate model, we have demonstrated that ocean temperature anomalies in the tropical and north Atlantic Oceans contribute to the distinctive fluctuations observed in the 2000s as above, while the direct contribution to modulation of the tropical cyclone activity is not significantly detected. In our decadal hindcasts with initialization, the climate model predominantly simulates a different type of fluctuations in any decade, and the resultant low predictability of the subdecadal variation in the 2000s can work to modulate the predictive skills at a lead time of several years.
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| Free Research Field |
気候力学
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| Academic Significance and Societal Importance of the Research Achievements |
熱帯太平洋の気候、とりわけ西太平洋の大規模気候や熱帯低気圧活動は日本を含めて広く注目を集めてきた。一方、近年の気候モデル研究では、従来は個別の議論が盛んであった各大洋間の相互作用が注目を集めてきた。本研究は、数年から十年規模という独自の時間スケールに注目して2000年代に特異な変動を見つけるとともに、気候モデルに観測データを融合するペースメーカー実験により、大洋間結合のひとつとして熱帯大西洋および北大西洋からの影響を指摘した。この特異な変動は十年規模気候予測の予測スキルに年代差を生み出すことも示しており、気候変動物理そのものに加えて気候予測精度の観点からも意義深い。
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