1998 Fiscal Year Final Research Report Summary
Global mapping of diapycnal mixing rates in the deep ocean for accurate modeling of the oceanic general circulation
| Project/Area Number |
09640520
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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 | The University of Tokyo |
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Principal Investigator |
HIBIYA Toshiyuki The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (80192714)
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| Project Period (FY) |
1997 – 1998
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| Keywords | internal wave spectrum / energy cascade / nonlinear wave interactions / diapycnal diffusivity / ocean general circulation model / parameterization / near-inertial internal waves / midlatitude storms |
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| Research Abstract |
By using three-dimensional numerical models, the distribution of internal wave energy for diapycnalmixing in the deep waters of the North Pacific has been examined. During winter, energetic near-inertial waves are excited in response to the midlatitude storms in the western-central North Pacific (30ﾟN-45ﾟN). Thus excited waves propagate southward down to 10ﾟN-15ﾟN where the frequencies become double the local inertial frequencies so that large amount of wave energy cascades down to dissipation scales via Parametric Subharmonic Instability mechanism. The low-vertical-wavenumber double-inertial frequency internal waves are, in contrast, very weak at the times and locations of the previous microscale measurements so that the observed diapycnal diffusivity of-0.1 cm^2s^<-1> might not be representative.
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