2023 Fiscal Year Final Research Report
Reproducing the climate variability of Chichi-jima and Haha-jima at Ogasawara (Bonin) Islands based on the analysis of meteorological data and old documents
| Project/Area Number |
21H00630
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 04010:Geography-related
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
菅野 洋光 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境研究部門, 再雇用職員 (30355276)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 気象データ / 古文書 / 小笠原諸島 / 父島，母島 / 気候変動 |
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| Outline of Final Research Achievements |
(1) Using meteorological data at Ohgiura, Chichi-jima, we investigated the long-term variability of precipitation at Chichi-jima after the end of 19th century. Precipitation at Chichi-jima has been decreasing during the 20th century, however, precipitation at the end of 19th century showed smaller value as well.
(2) Meteorological observations before June 1906 at Chichi-jima was conducted at Ohgiura, which was about 3 km southeast of Ohmura where Chichi-jima Meteorological Observatory is currently located. To connect both data at Ohgiura and Ohmura, we have carried out meteorological observations at Ohgiura. Precipitation at Ohgiura is systematically larger than that at Ohmura.
(3) Using NOT-publicly available precipitation data at Haha-jima after 1973, along with open precipitation there, we investigated the long-term variability of precipitation at Haha-jima and Chichi-jima. During 1973-2022, both precipitation at Haha-jima and Chichi-jima show significant increasing trend (p < 0.05).
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| Free Research Field |
自然地理学，水文気象学，地理情報科学
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| Academic Significance and Societal Importance of the Research Achievements |
従来の研究では，20 世紀中の父島の降水量は第二次世界大戦を境に，戦後の方が少なくなってきたことが指摘されていた．しかしながら，本研究によって 19 世紀末も降水量が少ない時期であることが分かった．
降水量が単調減少なのか周期的変化なのかは，動物や植物の生態を考えるうえでも貴重な情報である．小笠原には動植物の固有種も多く，本研究はそういった分野にも貢献すると考えられる．
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