2003 Fiscal Year Final Research Report Summary
Study on Ocean Current Minitoring with Variations of Sea Level etc.
| Project/Area Number |
11205202
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAWABE Masaki The University of Tokyo, Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (40143549)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Akio Polytec college Sendai, President, 校長(研究職)
YAMASHIRO Toru Kagoshima University, Department of Ocean Civil Engineering, Associate Professor, 工学部, 助教授 (20158174)
FUJIO Shinzou Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (00242173)
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| Project Period (FY) |
1999 – 2002
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| Keywords | Kuroshio Monitoring / Sea level data / Ferry in the Tokara Strait / Variations of current path / Current velocity, transport |
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| Research Abstract |
1. We made real-time Kuroshio monitoring system on the Internet, in which time series of oceanographic data such as sea levels are. shown in terms of current path, velocity, and volume transport of the Kuroshio. We can see time variations of the Kuroshio in high resolution, and can also access to maps of monthly temperature in the NEAR-GOOS database of the Japan Meteorological Agency and semimonthly Kuroshio state in the Quick Bulletins of Oceanographic Conditions issued by the Japan Hydrographic and Oceanographic Department.
2. Small meander of the Kuroshio generated south of Kyushu and propagating eastward is a major feature of the Kuroshio, and plays a great role in formation of the Kuroshio large meander. We clarified that the small meander can be monitored by the third mode of the Frequency Domain Empirical Orthogonal Functions for the coastal sea levels between Kyushu and the Boso Peninsula. This monitoring is included into the Kuroshio monitoring system.
3. We continued to measure the Kuroshio velocity south of Kyushu every two days, using the shipboard acoustic Doppler current profiler (ADCP) equipped with the ferry 'Akebono', and examined velocity profiles.
4. We considered how to estimate tidal currents in the Tokara Strait, in order to remove them from the ferry current data. We first analyzed past current-meter data and concluded a dominance of the M_2 tide. Then we measured full-depth current velocity at two points in the Tokara Strait using moored ADCPs, and clarified that the barotropic mode is most dominant in tidal currents, and the baroclinic third mode is secondly large with thirty percent of the barotropic amplitude. If the barotropic mode is estimated from tide-gauge data, and the relative amplitude and phase of baroclinic modes are expressed with position of the Kuroshio axis, tidal currents at any apace and time are possibly estimated.
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