2020 Fiscal Year Final Research Report

Pacific Ocean state estimation and clarification of mechanism of ocean circulation by data synthesis of global observations

Planned Research

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Project Area	Ocean Mixing Processes: Impact on Biogeochemistry, Climate and Ecosystem
Project/Area Number	15H05819
Research Category	Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Allocation Type	Single-year Grants
Review Section	Complex systems
Research Institution	Japan Agency for Marine-Earth Science and Technology
Principal Investigator	MASUDA Shuhei 国立研究開発法人海洋研究開発機構, 地球環境部門(海洋観測研究センター), センター長 (30358767)
Co-Investigator(Kenkyū-buntansha)	長船哲史国立研究開発法人海洋研究開発機構, 地球環境部門(海洋観測研究センター), 研究員 (50638723)
Project Period (FY)	2015-06-29 – 2020-03-31
Keywords	海洋観測 / データ同化 / 鉛直混合 / 深層循環 / 海洋鉄
Outline of Final Research Achievements	We conducted four research cruises on the research vessel Mirai during the research period. We completed turbulence observation as a standard observation item, which has rarely been conducted in large-scale shipboard observations in the past, and obtained high-precision data. By using the data obtained in the Grant-in-Aid for Scientific Research on Innovative Areas, we tried the data synthesis of the observed ocean turbulence dissipation rate ε, which is unprecedented. We have re-assessed the interpretation of the properties of the observed turbulent dissipation rate data by making use of recent statistical knowledge, and have established an application method for data assimilation. The integrated data set has successfully reproduced the global bottom water warming, which has not been reproduced by other systems. In addition, through collaboration with other research groups, we were able to reproduce the three-dimensional distribution of iron in the ocean.
Free Research Field	海洋物理学
Academic Significance and Societal Importance of the Research Achievements	海洋乱流データの性質を統計的に再検証する際に、一つのプロファイルから多くの独立情報を取得し、統計的性質を抽出する方法を認識できた点で、他の変量のデータ同化にも活用できる概念であり、今後の海洋データ同化、観測データの力学補間によるマッピングを飛躍的に効率化する可能性がある。深層昇温を今までにないレベルで再現出来たことは、温暖化に伴う地球全体でのエネルギーバジェットの精緻化に向けた重要な一歩である。IPCC報告などでの地球システムにおける深層の役割を解明するためのユニークな貢献が期待できる。