Study on the Mechanism of Crawling up of the Kuroshio Deep Water in the Continental Slope Area
| Project/Area Number |
03640386
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | NAGASAKI UNIVERSITY |
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Principal Investigator |
MATSUNO Takeshi NEGASAKI UNIVERSITY, FACULTY OF FISHERIES, ASSOCIATE PROFESSOR, 水産学部, 助教授 (10209588)
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| Co-Investigator(Kenkyū-buntansha) |
KANARI Seiichi HOKKAIDO UNIVERSITY, FACULTY OF SCIENCE, PROFESSOR, 理学部, 教授 (70027233)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1992: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1991: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | Kuroshio deep water / Continental slope / Crawling up / Internal tide / Vertical eddy diffusivity / Energy dissipation rate / Bottom mixed layer / 大陸棚斜面 / 鉛直混合 / 微細構造 / 東シナ海 / 係留観測 / 数値モデル |
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| Research Abstract |
Vertical distribution of the energy dissipation rate measured near the slope region indicated that the dissipation rate could be large in the bottom mixed layer, and the vertical mixing should be vigorous just above the bottom. The vertical eddy diffusivity estimated just above the bottom was sometimes more than 10 cm^2s^<-1>.
Vertical structure of internal tides near the continental slope was examined by current meters moored near the upper part of the continental slope. And it was suggested that the structure should varied in dependent with the variation of the location of Kuroshio's passage particularly at the layer just above the sloping bottom, while in the middle layer, near the thermocline it was recognized that the internal tides should be intensified during the spring tide. Such intermittent internal tides just above the bottom may occur when the density structure near the sloping bottom should be near critical.
It was not recognized that the tip of the low temperature water mas
… More
s crawling up to continental shelf break oscillated back and forth accompanied with the tidal current. The second thermocline characterized by the upper and of the crawling up water oscillated vertically, and the thickness of the bottom mixed water varied by means of the internal tidal motions.
From the current data obtained by current meters moored just above the bottom near the shelf break, it was shown that the averaged flows with a time scale longer than 25 hours had an up-slope component just above the bottom near the shelf break, though they had offshore component at the upper layers. This may be an evidence that the crawling-up low temperature water should be formed by the up-slope component of the current just above the sloping bottom.
Two-dimensional numerical model was developed to examine the formation of the up-slope flow near the slope area. Numerical experiments indicated that up-slope secondary flow near the bottom around the shelf break should be formed when the time scale of vertical mixing is shorter than the inertial period. Less
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Report
(3 results)
Research Products
(5 results)
