2003 Fiscal Year Final Research Report Summary
The role of double diffusive convection on the mixing processes in the ocean
| Project/Area Number |
14540405
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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 | Tokyo University of Marine Science and Technology |
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Principal Investigator |
YOSHIDA Jiro Tokyo University of Marine Science and Technology, Faculty of Marine Sciences, Professor, 海洋科学部, 教授 (30174931)
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| Co-Investigator(Kenkyū-buntansha) |
KITADE Yujiro Tokyo University of Marine Science and Technology, Faculty of Marine Sciences, Professor, 海洋科学部, 助教授 (50281001)
NAGASHIMA Hideki Tokyo University of Marine Science and Technology, Faculty of Marine Sciences, Professor, 海洋科学部, 教授 (10087570)
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| Project Period (FY) |
2002 – 2003
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| Keywords | WOCE Data Set / Density Ratio / Double Diffusive Convection / Salt Finger / Diffusive Convection / North Pacific Intermediate Water / Lateral Diffusion / Cabbeling |
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| Research Abstract |
The activity of double diffusive convection was investigated through the global density ratio distribution using the WOCE data set. In total, about 43% of the oceanic layers are favorable for the onset of double diffusive convectin, suggesting the important role on the global ocean circulation and the water mass modification processes. Our results are compared with those obtained from the Levitus climatological data set, and was coincided with the basin scale distribution. However, as for the sharp oceanic frontal area which are usually smoothed out from the Levitus data set, our results showed the possibility of high activity of double diffusive convection.
Neutral surface analysis and turbulent mixing analysis were applied for the Oyashio region to the Kuroshio Extension, which reveals the important role of cabbeling and salt finger convection to the modification process of the Northa Pacific Intermediate Water(NPIW). It is concluded that the Oyashio winter mixed layer water (26.65σθ) contributes to the freshening of the lighter layer than the salinity minimum of the NPIW (26.80σθ) and could not become the salinity minimum of the NPIW by the cabbeling and the double diffusive convection.
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