2018 Fiscal Year Final Research Report

Holocene atmospheric-ocean variability reconstruction from high-resolution analyses of stalagmites and corals in the Ryukyu Islands

Research Project

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Project/Area Number	26707028
Research Category	Grant-in-Aid for Young Scientists (A)
Allocation Type	Partial Multi-year Fund
Research Field	Stratigraphy/Paleontology
Research Institution	Tohoku University (2017-2018) University of the Ryukyus (2014-2016)
Principal Investigator	Asami Ryuji 東北大学, 理学研究科, 准教授 (00400242)
Research Collaborator	Uemura Ryu 名古屋大学 Shinjo Ryuichi 琉球大学 Iryu Yasufumi 東北大学 Shen C.-C. 国立台湾大学
Project Period (FY)	2014-04-01 – 2019-03-31
Keywords	古環境 / 古気候 / 石筍 / サンゴ / 第四紀 / 完新世 / モンスーン
Outline of Final Research Achievements	In order to evaluate the present and future global environment, it is important to understand climate change from the past to the present. Therefore, to understand the environmental change in the East Asia-Northwest Pacific region during the last glacial and the Holocene (about 20,000 years ago to today), highly-accurate and -resolution analyses of chemical composition in stalagmites in the limestone caves of the Ryukyu Islands were performed in this study. As a result, robust time series of thermal and hydrological variations showing post-glacial climate change was successfully generated. Coupled together with geological data from marine organisms such as corals, an index of the marine environment, this study showed a reconstruction of the atmospheric-ocean variability history around the Ryukyu Islands showing the East Asian summer/winter monsoon and decades-scale variability.
Free Research Field	古環境学
Academic Significance and Societal Importance of the Research Achievements	琉球列島はモンスーンや台風の影響を受ける気候学的に極めて重要な地域である．本研究では，高分解能かつ高精度の年代測定と化学分析によって，長期の石筍データ（約2万年前～現在にかけての気候変動記録）を復元した．これは，世界最高水準のデータセットかつ北西太平洋亜熱帯域における代表的な基準資料となりうるため，地球環境研究や気候シミュレーション研究の進展に貢献する点で学術的意義が大きい．また本研究は，人類が抱える環境問題「温暖化」や，海洋立国である我が国の気候に影響する「黒潮」「台風」「モンスーン」，沖縄の人と生活に関わる「サンゴ礁」と密接に関連しており，学術面のみならず社会面双方に対して意義がある．