Thermal behaviour of glacier and laboratory ice
Thermal behaviour of glacier and laboratory ice
复制标题
冰川和实验室冰的热行为
DOI：
10.3189/s0022143000005839
复制
发表时间：
1991
影响因子：
3.4
通讯作者：
J. Nye
中科院分区：
文献类型：
--
作者：
J. Nye
摘要冰川中的水是以三粒交界处的脉状存在的。这些水即使在正常冰点以下几度也不会结冰，主要是因为它含有冰川中的大部分可溶性杂质，但也因为冰水界面的微观曲率。随着温度的降低和脉纹的收缩，其中的杂质浓度增加，曲率效应也增加。预测的矿脉尺寸与温度之间的关系现已被实验室实验所证实。由于脉水的潜热，冰在宏观上表现为具有异常比热容的连续体，该比热容强烈依赖于温度。从这个角度来看，多温冰川是一种具有连续变化特性的单一介质，而不是由不同的冷、温带阶段组成，它们之间有明显的边界。本文建立了这种连续介质中热扩散的微分方程。为了解释显微镜下所见的矿脉系统的局部均匀性，发现有必要包括溶质沿着矿脉扩散的影响。解决方案的模型中，两个半无限板，最初具有不同的温度，杂质浓度和静脉大小，瞬间接触。通过这种方式，冷和温和的冰之间的过渡厚度的估计，也是各种波的速度，从原始的界面处的不连续性产生的。
Abstract Water is present in glaciers in the form of veins at the three-grain junctions. This water remains unfrozen even many degrees below the normal freezing point, mainly because it contains much of the soluble impurity content of a glacier, but also because of the microscopic curvature of the ice–water interfaces. As the temperature is lowered and the veins shrink, the concentration of impurities in them increases, and the curvature effect also increases. The predicted relation between vein size and temperature has now been verified by laboratory experiments. Because of the latent heat of the vein water, the ice behaves macroscopically as a continuum with an anomalous specific heat capacity that depends strongly on temperature. From this point of view, a polythermal glacier is a single medium with continuously varying properties, rather than consisting of distinct cold and temperate phases with sharp boundaries between them. The paper sets up differential equations for heat diffusion in such a continuum. To explain the local uniformity of the vein system seen under the microscope, it is found necessary to include the effect of diffusion of solutes along the veins. Solutions are presented for a model in which two semi-infinite slabs, initially having different temperatures, impurity concentrations and vein sizes, are instantaneously brought into contact. In this way, transition thicknesses between cold and temperate ice are estimated, and also the velocities of various kinds of waves that are generated from the original discontinuity at the interface.