| Project/Area Number |
10650911
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
海洋工学
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| Research Institution | Yuge National College of Maritime Technology |
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Principal Investigator |
TSUKAMOTO Hideshi (1999) Yuge National College of Maritime Technology, Department of Science and Information Technology, Associate Professor, 情報工学科, 助教授 (20311102)
秋山 秀樹 (1998) 弓削商船高等専門学校, 商船学科, 助教授 (90159343)
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| Co-Investigator(Kenkyū-buntansha) |
SEIDA Kouji Hiroshima National College of Maritime Technology, T/S Hiroshima-MARU, Assistant Professor, 練習船広島丸, 助手 (50216503)
SETO Junzo Hiroshima National College of Maritime Technology, T/S Hiroshima-MARU, Associate Professor, 練習船広島丸, 助教授 (80249846)
TADA Mitsuo Yuge National College of Maritime Technology, Department of Maritime Technology, Associate Professor, 商船学科, 助教授 (60141941)
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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 |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1998: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Bungo Channel / Saiki Bay / Topographic Eddy / Tide and Tidal current / upwelling / sudden increase in temperature / Kuroshio Warm Water / 内湾 / 現地調査 / 超音波ドップラー流速計 / 水温・塩分断面構造 |
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| Research Abstract |
We performed the field observations in Saiki Bay of the western side of the Bungo Channel during a summer of 1998 and 1999. The CTD and ADCP observations were carried out under consideration of the same period of semi-diurnal tide. The mooring temperature observations were also carried out at the middle and the mouth of the bay from sub-surface to near-bottom. Moreover, the sea surface temperature (SST) data obtained by using the ferryboat navigating across the channel were analyzed.
The physical structures related to the topographic eddies in Saiki Bay are found as follows ; (1)The topographic eddy is formed in the whole bay with an anti-clockwise (clockwise) circulation when the Bungo Channel is for the flood (ebb) tidal current. (2)Kuroshio warm water intrudes into the upper layer of the bay and the cool water also intrudes into the lower layer when the channel is for the flood tidal current. (3)When the eddy is formed in the whole bay, the cold lower layer water intruded from the bottom of the channel is up welled to the middle layer in the center of the eddy. (4)Such an upwelling event suddenly happens within a short duration. (5)The eddy is in the shape of an upside-down cone. That vertical axis inclines towards the mouth of the bay from the sea surface to the bottom along the bottom topography.
Other concerned results are as follows ; (6)The SSTs in Saiki Bay are lower than other three sea areas in the Bungo Channel, where are in the center and the eastern parts of the channel and in Sukumo Bay. (7)Lower SST zones are locally appeared at the center of Saiki Bay and around Cape Koumo-misaki, northwestern part of Sukumo Bay. (8)Tidal front is maintained at the mouth of Saiki Bay from March to November. Especially, the tidal front is to become sharp there from June to September.
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