| Project/Area Number |
02452060
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 Institute of Polar Research (N.I.P.R.) |
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Principal Investigator |
WATANABE Okitsugu N.I.P.R., Professor, 研究系, 教授 (60111861)
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| Co-Investigator(Kenkyū-buntansha) |
KAMIYAMA Kokichi N.I.P.R., Assistant, 研究系, 助手 (70135507)
MOTOYAMA Hideaki N.I.P.R., Assistant, 研究系, 助手 (20210099)
FUJII Yoshiyuki N.I.P.R., Associate Professor, 研究系, 助教授 (20125214)
西尾 文彦 国立極地研究所, 資料系, 助教授 (40044789)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1992: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1991: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1990: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Snow-Ice Core / Climatic Change / Environmental Change / Ice Core Study / Antarctic Ice Sheet / Arctic Region / Tephrochronology / Climatic and Environmental Signals / 気候変動復元 / 氷床コア / 環境変動 / 火山灰編年 / 北極地域 / 南極地域 / 氷床の堆積環境 / 極域雪氷圏 / 火山活動シグナル / 氷床気候 |
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| Research Abstract |
The ice sheets and glaciers were constructed under the various conditions depending upon the local climatic environments in the region. By identify the sedimentary environments in various regions, the ice core analyses possibly make clear the global environments as well as the local sedimentary environment. For the pursuit, it is necessary to treat the various ice cores with the same procedure and to give the cores the time scales not depending upon the local environments. We obtained various data from the ice cores in both polar regions, some of which were utilized for the estimations of core dating and of the past sedimentary environments. Recently with the progress of technology, the various kinds of data were newly obtained and used for the estimation. In the project, we consider the new methods now in progress, covering the classic methods, and try to find the standard core analytical methods for the cores in various regions at once. With the estimation of sedimentation rate, the
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first order dating for the whole ice core was carried out from the glacier flow models. Several time markers for the ice cores were determined from the information for the concentrations of the substances originating from the volcanic activities and of the artificial radio nuclides occurring in the ice layer. The final core dating was carried out by the mutual correlation with the flow models and the time markers. The vertical distributions of stable isotopes (deltaO^<18>) , the main components derived from the sea salts, micro particles and the artificial substances from human activities were obtained to estimate the fluctuations of the paleo temperature and precipitation rate as well as the sedimentary environments. The vertical fluctuations in the core were translated into periodical one by the core dating data to create the paleo global climate system in these hundred years including both polar regions. Recently the volcanic activities reflected in the ice core were considered to be the useful indicator to recognize the date of deposition, especially for the cores in Arctic region. Both of DC electric conductivity method and Dielectric profile method were utilized to the ice cores in both polar regions and some continuous data were obtained. Many signals of the volcanic activities were detected in the cores in Antarctica. Especially the signals from the activities of Tanbora(1815) and of Unknown(1601) were detected in both polar region with the recognized profiles and confirmed to be the marked layer for the dating in the Antarctic glaciers as well as the Arctic glaciers. As almost all signals have not been recognized yet, there remains much possibility for us to use as the time markers in the progress of the investigation. Though the sedimentary environments (hiatus periods, large fluctuation of the annual precipitation), which characterize the Antarctic glaciers, have made the core records more complicated, such an investigation will make the core data more us Less
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