Ice Movement and Temperature Distribution in Glaciers and Ice Sheets
Ice Movement and Temperature Distribution in Glaciers and Ice Sheets
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DOI：
10.3189/002214355793702028
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发表时间：
1955-10
影响因子：
3.4
通讯作者：
N. G. Lac;IE R San;D. I. She;S. Et
中科院分区：
文献类型：
--
作者：
N. G. Lac;IE R San;D. I. She;S. Et
摘要 考虑了整个冰盖的温度分布，考虑了冰运动的影响以及之前考虑的其他因素，例如传导、热量的地热流出以及冰运动产生的热量。通过某些简化假设，提出了一种估计冰盖中心附近温度分布的定量方法。结果表明，即使年平均积累量很小，也会对大冰盖的温度分布产生相当大的影响。对于中等的积累速度，大冰盖中心的冰总厚度的很大一部分在主要的表面冰温度下可能是等温的。在这些条件下，距中心一定距离处，表面冰温随海拔的变化可能会产生与正常情况相反的温度梯度，即由于冰向外运动，温度随着表面以下深度的增加而下降。观测到的冰盖温度梯度大致符合所提出的假设，但似乎还应考虑气候变化。有人认为，冰盖底部温度从熔点以下上升可能可以解释某些冰川偶尔出现的灾难性进展。
Abstract The distribution of temperature throughout an ice sheet has been considered, taking into account the influence of ice movement as well as other items previously considered, such as conduction, the geothermal outflow of heat and heat generated by ice movement. By making certain simplifying assumptions, a quantitative method of estimating the temperature distribution near the centre of an ice sheet has been put forward. It is shown that even a small mean annual accumulation will have considerable effect on the temperature distribution in a large ice sheet. For a moderate rate of accumulation a substantial fraction of the total thickness of ice at the centre of a large ice sheet may be isothermal at the prevailing surface ice temperature. Under these conditions at some distance from the centre, the change in the surface ice temperature with elevation may produce a temperature gradient opposite to normal, that is the temperature falls with increasing depth below the surface, due to the outward movement of the ice. Observed temperature gradients on ice sheets fit the proposed hypotheses roughly, but it appears that climatic change should also be taken into account. It is suggested that a rise from temperatures below melting point at the base of ice sheets may provide an explanation of the occasional catastrophic advances of certain glaciers.