2016 Fiscal Year Final Research Report
Overturning circulation that connects the surface and intermediate layers in the North Pacific: A new perspective on its three-dimensional structure and variability
| Project/Area Number |
26247076
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
中村 知裕 北海道大学, 低温科学研究所, 講師 (60400008)
西岡 純 北海道大学, 低温科学研究所, 准教授 (90371533)
西垣 肇 大分大学, 教育福祉科学部, 准教授 (70253763)
美山 透 国立研究開発法人海洋研究開発機構, 地球環境変動領域, 研究員 (80358770)
伊藤 進一 東京大学, 大気海洋研究所, 教授 (00371790)
和川 拓 国立研究開発法人水産研究・教育機構, その他部局等, 研究員 (10601916)
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| Co-Investigator(Renkei-kenkyūsha) |
Fujii Yousuke 気象研究所, 主任研究員 (60343894)
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| Research Collaborator |
Nakanowatari Takuya 国立極地研究所, 国際北極環境研究センター, 研究員 (20400012)
Nishikawa Hatsumi 北海道大学, 低温科学研究所, 博士研究員 (10783392)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 海洋科学 / 北太平洋 / 子午面循環 / 準定常ジェット / 高塩水輸送 / 物質輸送 / 海底地形 |
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| Outline of Final Research Achievements |
This study aimed to elucidate the overturning circulation originating in the Sea of Okhotsk that ventilates the intermediate layer of the North Pacific Ocean, where strength of the overturn is determined by salinity. However, our knowledge regarding salt transport pathways from low latitude to high latitude was still lacking. Here we present a salt pathway paying attention to the quasi-stationary jets in the transition region between the subtropical and subarctic gyres. The quasi-stationary jets flow northeastward regulated by bottom topography whose height is only 500 m although the ocean is deep. We have elucidated this process using theoretical models, numerical experiments and drifting buoy measurements. Numerical and chemical tracer analyses show that the saline Kuroshio waters are transported to the subarctic gyre through the quasi-stationary jets. The overturn is likely strengthened when the westerly wind is strengthened because of increase of the northward salt flux.
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| Free Research Field |
海洋物理学
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