| Project/Area Number |
08454127
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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 | Kitami Institute of Technology |
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Principal Investigator |
SHOJI Hitoshi Fac.Eng., Kitami Institute of Technology Professor, 工学部, 教授 (50201562)
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| Co-Investigator(Kenkyū-buntansha) |
NARITA Hideki Hokkaido Univ., Inst.Low Temp.Sci., Associate Professor, 低温科学研究所, 助教授 (20001662)
KAMEDA Takao Fac.Eng., Kitami Institute of Technology Assistant, 工学部, 助手 (00233974)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1997: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1996: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | ice core / ice sheet flow / cloudy band / global environment / Summit core |
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| Research Abstract |
A long-term environmental record on the Earth can be obtained from Greenland ice sheet studies. A continuous deep ice core was retrieved at Summit, Central Greenland by GRIP in 1992. Core analysis reveals abrupt climatic fluctuations existed during Eemian/Sangamon interglacial period. However, a possibility that this is an artifact caused by complica ted flow behaviors near the ice sheet bottom is also pointed out.
This study revealed the following findings under an international research collaboration with other GRIP members.
1) Mechanical property studies showed the following results.
・Ice sheet flow is dominated by crystallographic anisotropy of ice in plastic deformation processes.
・ Impurity concentration type/level affects the formation process of crystal orientation distribution characteristics associated with the stess field in the ice sheet.
・ Differential flows in a small scale exist near cloudy bands.
2) A new flow law is obtained by using laboratory test results of core samples for ice sheet dynamics considerations. The application of this law to the Summit position shows that ice flow just above the complicated bottom tends to be unstable easily and the flow is quite sensitive to the bottom topography.
3) A detailed core analysis on the Summit core, considering the above ice flow behaviors and other core data shows that at least one abrupt climatic change during Late Eemian is real. Further studies are planned and proceeded by performing the North GRIP project.
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