2001 Fiscal Year Final Research Report Summary
Study on three dimensional structure of high and mid-latitude ocean circulation under idealized situation
| Project/Area Number |
12640416
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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 UNVERSITY |
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Principal Investigator |
KUBOKAWA Atsushi Hokkaido Univ., Grad. School of Env. Earth Sci., Pro., 大学院・地球環境科学研究科, 教授 (00178039)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Ocean circulation / Ventilated thermocline / Eastern boundary / Vertical density diffusion / Planetary waves / Oceanic response |
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| Research Abstract |
Numerical experiments using an idealized OGCM were carried out to investigate the three dimensional structure of ocean circulation. The model ocean was driven by both wind and surface buoyancy forcing, and deep water formation in the southern hemisphere was included. The results show that the eastern boundary is a source of subsurface water : the water subducted at the eastern boundary flows equatorward along the boundary and then turns westward into the oceanic interior region. This equatorward flow occurs without wind forcing. The analysis based on the potential vorticity balance suggests that the vertical density diffusion is important for generating this current. Sensitivity study of the model results to the vertical diffusion and a theoretical study based on a linear model were also carried out to confirm this idea.
In addition to the above work, linear planetary wave dynamics in a 2.5-layer ventilated thermocline model was theoretically investigated to consider the oceanic thermocline variability. After describing the local properties of the waves, wave propagation in a oceanic gyre and oceanic response to atmospheric forcings were discussed. Effects of finite wave length on the wave properties and stabilities were also studied.
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