2018 Fiscal Year Final Research Report
Presumption of turbulent kinetic energy in the Arctic Ocean: Evaluation of ice retreat and growing large-scale ocean circulation
| Project/Area Number |
16K21700
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
Environmental dynamic analysis
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| Research Institution | The University of Tokyo (2017-2018)
Japan Agency for Marine-Earth Science and Technology (2016) |
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Principal Investigator |
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| Research Collaborator |
NISHINO Shigeto
FUJIWARA Amane
ITOH Motoyo
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 北極海 / 慣性振動 / 内部重力波 / 海水 / 乱流混合 / エネルギー散逸 / ウェーブレット |
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| Outline of Final Research Achievements |
In this study, we performed mooring and shipboard observations to elucidate the variation of sea ice volume and ocean mixing in the Arctic Ocean. We closely analyzed the data records from the mooring system, that was situated in the Pacific section of the Arctic, where ice retreat has been observed in the most prominent way. The data demonstrated the remarkable elevation in internal wave and turbulent kinetic energy in the upper water. We interpret that the high energy level is due to the expansion in the momentum exchange between ice and air. The increased turbulent energy was observed particularly during early summer and early freezing period, when sea ice was rarely present. In the time, ice drift is relatively faster as response to the surface wind. Consequently, we concluded that the faster ice drift produced highly energetic internal waves in the upper part of ocean column, at the similar frequency.
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| Free Research Field |
極域海洋物理学
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| Academic Significance and Societal Importance of the Research Achievements |
上述のように、地球温暖化の影響で海氷が著しく減少し続ける北極海において、海洋が大気に接する時間が増加することは自明である。変化が著しい北極海において、海洋がこの変化にどのように応答しているのか？と言う問いに対して、係留系を用いた直接的な海氷や海洋流速の現場観測を執り行い、通年におよぶ貴重な実測データを取得した。その詳細なデータ解析から、北極海の海洋では、地球温暖化に端を発した海氷減少の影響がすでに中・深層にまでおよび始めていることを提示できた点は、学術コミュニティのみならず社会全体に与える影響力は決して小さくないと考える。
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