| Project/Area Number |
16540393
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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 |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | Hokkaido University |
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Principal Investigator |
KUBOKAWA Atsushi Hokkaido University, Faculty of Environmental Earth Science, Professor, 大学院地球環境科学研究院, 教授 (00178039)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | eddy-resolving model / western boundary current / eastward jet / mixed-layer depth front / subduction / bottom topography / seasonal variation / 海洋循環構造 / 混合層前線 / 年周期変動 / 惑星波 / 西岸境界流 / 続流ジェット / 海洋中規模渦 / 陸棚斜面 / 海洋混合層 |
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| Research Abstract |
In order to understand the ocean circulation dynamics in idealized configurations, we carried out the following three studies.
1.Ocean circulation in an eddy-resolving model-Adopting a two-layer quasigeostrophic model driven by anti-symmetric Ekman pumping, a numerical solution with double eastward jets which are prematurely separated from the western boundary was obtained when the inertial boundary layer thickness is realistic and viscous western boundary layer is not very thin, as well as a solution with a single eastward jets along the inter-gyre-boundary. The latitude of the eastward jet of double-jet solution is insensitive to parameters, and strongly depends on the meridional profile of the wind forcing. A parameter region where both the single-jet and double-jet solutions coexist was found.
2.Upper-layer ocean structure in an idealized ocean GCM-" Focusing on the mixed-layer depth (MLD) front, we investigated the MLD distribution and subduction of low PV water. It was found that the MLD front occurs along a curve where the upper-layer geostrophic current flows parallel to outcrops. The water subducted at the MLD front does not cross the outcrop, different from that expected from the ventilated thermocline theory. The effect of seasonally variable forcing on the MLD distribution was also investigated.
3.Effects of bottom topography: It was found that the mass transport of a western boundary current over a slope in high latitude almost coincides with the annual mean Sverdrup transport in a weak wind season, while it coincides with instantaneous Sverdrup transport in strong wind season, if we define the transport as the integrated current from the coast to a point where the current direction changes. Rossby waves over a one-dimensional periodic topography were also investigated.
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