| Project/Area Number |
63540312
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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 | Mie University |
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Principal Investigator |
FUKUYAMA Kaoru Mie University, Dept. of Earth Sciences, Associate Professor, 教育学部, 助教授 (00189979)
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| Co-Investigator(Kenkyū-buntansha) |
KASHIWAYA Kenji Kobe University, The Graduate School of Science and Technology, Senior Research, 自然科学研究科, 助手 (30161029)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Paleoclimatic change / Pleistocene / Milankovitch theory / Lake Biwa / Quasi-periodic variations / Geological sediments / Grain size distribution / Glacial-interglacial change / 第四紀更新世 / 粒度分布 / 同位体比 / 日射量の永年振動 / 氷期と間氷期 |
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| Research Abstract |
We have analyzed statistically several sedimentation data which record different aspects of late Pleistocene climatic variations. A spectral analysis has been applied to grain size data from a Lake Biwa sediment core, a marine delta^<18>O record from the equatorial central Pacific, a hydrospheric delta ^<18>O record in a calcite vein, and atmospheric CO_2 concentration and surface temperature change from an antarctic ice core. On the basis of the results of spectral analysis we performed a multi-linear, periodic regression analysis to obtain more plausible values of the dominant periods, and their amplitudes and phases. The results show that almost all the climatic records can be represented by a superposition of several periodic oscillations : the Milankovitch precession (ca 20-ky period) and obliquity (ca 40-ky period) cycles as well as oscillations of 120-130-ky, 60-70-ky and ca 30-ky periods. The Pleistocene glacial- interglacial change seems to be not interpreted by a simple 100-ky cycle, but by a combination of strong 120-130-ky and moderate 60-70-ky oscillations on which are superimposed the Milankovitch (precession and obliquity) and 30-ky cycles. Differences in relative magnitude and phase of predominant periodic components in different climatic records may reflect local climates and physical mechanisms responsible for variation in individual climatic parameters.
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