| Project/Area Number |
09440165
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
HANAWA Kimio Graduate School of Science, Tohoku University, Professor, 大学院・理学研究科, 教授 (40142921)
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| Co-Investigator(Kenkyū-buntansha) |
KIZU Shoichi Graduate School of Science, Tohoku University, Research Associate, 大学院・理学研究科, 助手 (40241517)
SUGA Toshio Graduate School of Science, Tohoku University, Associate Professor, 大学院・理学研究科, 助教授 (70211977)
EBUCHI Naoto Graduate School of Science, Tohoku University, Associate Professor, 大学院・理学研究科, 助教授 (10203655)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1998: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Keywords | Kuroshio / GPS / dynamic height / XBT / ADCP / mesoscale eddy / Subtropical Mode Water / monsoon / 中規模渦 / 高度計 / 海面高度 / GPS(汎地球測位システム) / 海面力学高度 / TOPEX / POSEIDON衛星 / ADCD / 潮流 |
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| Research Abstract |
In the present study, the following three items were carried out : (1) Precise measurement of sea surface height by GPS kinematic survey installed on a ferry boat, (2) clarification of mesoscale eddies in the studied area using ADCP data and TOPEX/POSEIDON altimeter data and (3) water mass structure and its variation in the studied area using the archived temperature data. Main results can be summarized as follows.
(1) Using the ferry Ogasawara Maru which shuttles between Tokyo and Ogasawara Islands, we carried out the GPS kinematic survey in September 1999. We could obtain the data suitable for analysis when the distance of two GPS stations (the reference station and the ferry) is short (shorter than hundreds km). However, it was found that the distance is relatively longer, the data are not suitable for analysis. From the data obtained when the ferry was anchored at Hutami Port, we could detect the tidal signal with enough accuracy.
(2) Using the ADCP data and TOPEX/POSEIDON altimeter data, we analyzed the mesoscale eddies in the Kuroshio recirculation area. We found a plenty of anticyclonic and cyclonic eddies whose diameter is approximately 500km. The temporal scale is estimated to be approximately 80 days. It was suggested these eddies are formed on the Kuroshio Extension area.
(3) Using the archived temperature data, we made the gridded temperature data and analyzed interannual variation of subtropical mode water with respect to the strength of wintertime East Asia monsoon. It was found that when the wintertime East Asian monsoon is strong (weak), thick (thin) and cold (warm) subtropical mode water is formed.
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