2023 Fiscal Year Final Research Report
Mysteries of baroclinic circulation in the upper ocean: Eastern South Indian Ocean
| Project/Area Number |
16K05562
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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 | Japan Agency for Marine-Earth Science and Technology |
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Principal Investigator |
Furue Ryo 国立研究開発法人海洋研究開発機構, 付加価値情報創生部門(アプリケーションラボ), グループリーダー代理 (30311640)
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| Project Period (FY) |
2016-04-01 – 2024-03-31
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| Keywords | 沿岸流 / 亜熱帯循環 / 波動力学 / 南東インド洋 |
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| Outline of Final Research Achievements |
The dynamics of the basin-scale circulation of the upper ocean is generally well understood in the classical framework of wind-driven general circulation. There are still knowledge gaps in the interaction of the general circulation with the coastal flows. This study has clarified how the Leeuwin Current, a surface, southward-flowing coastal current along the west coast of Australia, is a part of a shallow overturning circulation connecting the broad surface eastward flow and a matching subsurface westward flow. The pathway of the Leeuwin Undercurrent is described. In addition, a new shallow seasonal undercurrent is discovered on the continental slope of Northwest Australia and a new deeper seasonal variability is found that propagates counter-clockwise along the west, south, southwest, and east coasts of Australia. These variabilities potentially propagate westward from the coast. This issue will be an interesting subject for future studies.
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| Free Research Field |
海洋力学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は、豪州を例に取り、海盆の大循環とその東側の沿岸流の相互作用の一形態を明らかにし、また亜表層の大陸斜面に沿う季節変動流を二つ見つけたものである。ルーイン海流は密度駆動であるが、同様に密度駆動だと思われる他の沿岸流(ポルトガル沿岸など)にも応用できるかも知れない。ルーイン潜流は大陸斜面に沿うことをやめ急に沖に出てなくなってしまうことがはっきりしたが、この力学は不明である。一方、大陸斜面上の季節変動は、その励起源が不明であり、またどこまで伝わりどこで消散するのか・どの程度海盆内部へ伝わるのかも不明である。このような新しい研究題材を発見したといえる。
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