| Project/Area Number |
10480121
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
MIYAKE Hideo Hokkaido Univ., Fac, of Fis., Pro., 水産学部, 教授 (60002127)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Takashi Hokkaido Univ., Fac, of Fis., Inst., 水産学部, 助手 (70101136)
YANADA Mitsuru Hokkaido Univ., Fac, of Fis., Asso. Pro., 水産学部, 助教授 (00166555)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | vortex-pair flows / southeasterly / sediment transport / density-driven eddy / settling particles / organic matter / 沿岸流 / 南東風 |
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| Research Abstract |
Roles of wind-driven vortex-pair flows on the ecosystem and the sediment transport processes were investigated in Funak Bay. The rsults are summarized as follows:
(1) Coastal water at three station around the bay showed the leewind flows whenever southeasterly wind blew. While, in the same periods the deep water of 80 m depth at the bay center flowed windward. These facts agree well with vortex-pair flows suggested by the numerical simulation model.
(2) In the mid-summer, density driven-anticyclonic eddy dexeloped in the bay. The eddy showed a rigid body rotation and presumed to rotate aroud the bay center with 2.5 to 5 days period. The eddy was accurately maintained by geostrophic relation, and the coasta upwelling was suggested around the eddy.
(3) Coasatal currents were observed at two opposite sites across Hidaka Basin to clarify coastal trapped waves. Surface currents at both stations in June and July were explained by the first mode of the shelf waves. At the lower layers of both stations, however, northwestward flows alternated simultaneously with southeasteward flows with about ten days period. While, at the lower layers of both stations in October, coastal currents flowed opposite direction without significant time lag.
(4) Total mass fluxes increased abruptly during relative short time interval(2 to 4 days) in the bay center. These events seemed to relate closely to the meteorological and hydrographical conditons such as wind speeds, wind direction and wind waves. We presumed that southeasterly winds daving a long fetch, generate high wind waves around the northwest coast of the bay, and then the waves generate resuspentions of the bottom sediments. Finally, these sediments are transported to the bay center by the wind-driven vortex-pair flows.
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