2023 Fiscal Year Final Research Report
Tropical stratosphere-troposphere coupling through cirrus and its role in climate change
| Project/Area Number |
19K03977
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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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| Review Section |
Basic Section 17020:Atmospheric and hydrospheric sciences-related
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| Research Institution | Japan, Meteorological Research Institute |
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Principal Investigator |
Yoshida Kohei 気象庁気象研究所, 全球大気海洋研究部, 主任研究官 (10636038)
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| Co-Investigator(Kenkyū-buntansha) |
川合 秀明 気象庁気象研究所, 気象予報研究部, 主任研究官 (40601688)
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | 熱帯成層圏対流圏結合 / 巻雲 / 雲放射効果 / 気候モデリング / 気候変動 |
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| Outline of Final Research Achievements |
The cloud radiation effects associated with the cirrus clouds in the tropical tropopause layer warm this region and also have thermal effects on the troposphere, and these effects are intensified during global warming. They modulate the amplitude of the lower stratospheric quasi-biennial oscillation (QBO). Experiments with higher vertical resolution and modified physical processes show significant differences in the QBO easterly and westerly wind phase differences, especially in convective and related circulation indices near the equator in the Northern Hemisphere winter, from the maritime continents to the Indian Ocean. In the experiment with the same settings but excluding cloud radiation in the upper troposphere, the lower QBO amplitudes were larger, but no significant differences appeared in convective and other indices. This difference was not detected by the higher vertical resolution alone, indicating that the cloud radiation process of the cirrus clouds may be influential.
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| Free Research Field |
大気科学
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| Academic Significance and Societal Importance of the Research Achievements |
巻雲の重要性が示されたことで、気候モデルについて巻雲とその雲放射効果の再現性という観点で再考されるべき、というパラダイムシフトが期待される。さらに光学的な薄さから観測が難しい巻雲や氷晶核となるエアロゾルの詳細な分布と構造を調べる必要性が再認識され、観測のさらなる充実と数値モデル研究の進展との好循環が期待される。また気候モデルにおける物理過程の扱いの難しさや、成層圏対流圏結合の解析におけるサンプル数確保の重要性を示せたことも研究領域におけるパラダイムシフトの一助になったと考えられる。
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