| Project/Area Number |
02804025
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | National Astronomical Observatory |
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Principal Investigator |
NAITO Isao National Astronomical Observatory, Earth Rotation, Assit. Prof., 地球回転研究系, 助教授 (90000174)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | Earth Rotation / Chandler Wobble / Angular Momentum / QBO / Non-Linear / El Nino / 極運動 / 季節内変動 / 自転速度 / 不規則変動 / El Nino / コア・マントル結合 / 気象庁デ-タ |
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| Research Abstract |
The earth is a dynamically coupled system of atmosphere, hydrosphere, mantle and core under conservation of angular momentum. There are many observational facts that global changes in solid-earth system including core as well as in atmosphere-hydrosphere system have been closely connected with angular momentum exchanges between the above two systems.
In order to explain these facts, this paper presents a model that a non-linear feedback system of atmosphere-hydrosphere having a period-length doubling harmonics with the two typical spherical harmonics modes which excite the wobble and LOD controls excitation of the Chandler wobble and hence causes global changes in the solid-earth system such as change in worldwide seismic activity and geomagnetic change with periods of decades.
The observational facts reveal that the earth's dynamic coupling system causing these global changes may be closed in a period of about 40 years. The model can straight lead to a previous view that the present day climatic fluctuation closely correlated with the decades variations of the lengthof day and the wobble amplitude.
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