Flow dynamics near the bottom of Greenland ice sheet revealed by the Summit ice core analysis

关于地球可能从格陵兰冰表研究中获得的长期环境记录。1992年在峰会上发现了一个连续的深度冰芯，中格陵兰，GRIP。Core analysis reveals abrupt climatic fluctuations existed during Eemian/Sangamon interglacial period。怎么办，这是一个由complica ted flow行为引起的艺术品的可能性，靠近ice sheet底部的行为也很突出。本研究揭示了在与其他GRIP成员的国际研究合作下的后续发现。1）机械性质研究展示了以下结果。冰表流是由塑料变形过程中的冰的晶体学不同形态主导的。影响因素类型/水平影响与冰表中的应力领域相关的形成过程的形成过程。在靠近云波段的小尺度存在的差异流.2）新的流法被使用实验室测试结果的核心样本用于冰表动力学假设。这一法律对峰会位置的应用表明，冰流只是在复杂的底部趋势下变得不稳定，而流量对底部拓扑非常敏感。3）对峰会核心的详细核心分析，考虑到冰流上方行为和其他核心数据显示，至少有一个先前的气候变化在晚叶米安是真实的。进一步的研究是计划和进行的，由执行北GRIP项目。

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.