Thermal properties of a supraglacial debris layer with respect to lithology and grain size
Thermal properties of a supraglacial debris layer with respect to lithology and grain size
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DOI：
10.1111/geoa.12011
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
M. Juen;C. Mayer;A. Lambrecht;A. Wirbel;U. Kueppers
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文献类型：
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作者：
M. Juen;C. Mayer;A. Lambrecht;A. Wirbel;U. Kueppers
摘要本文从岩性和粒度两个方面研究了碎屑覆盖对冰融化的影响。建立了10个试验区，碎片粒度和厚度不同，由不同的天然材料组成。对于每个图，测定热导率值。观测结果表明，子碎片冰融化对层厚度、粒度、孔隙度和含水量的依赖性很明显。对于砂部分，水分含量起主导作用。这些测试场大部分时间都是水饱和的，导致热导率增加。高度多孔的火山物质比当地类似厚度的云母片岩更有效地保护了冰不被融化。然而，对热扩散率的分析表明，必须考虑到碎片覆盖层的垂直湿度分布，较深层的扩散率值要低得多。
Abstract This paper focuses on the impacts of debris cover on ice melt with regards to lithology and grain size. Ten test plots were established with different debris grain sizes and debris thicknesses consisting of different natural material. For each plot, values of thermal conductivity were determined. The observations revealed a clear dependence of the sub‐debris ice melt on the layer thickness, grain size, porosity and moisture content. For the sand fraction the moisture content played a dominant role. These test fields were water saturated most of the time, resulting in an increased thermal conductivity. Highly porous volcanic material protected the ice much more effectively from melting than similar layer thicknesses of the local mica schist. However, the analysis of thermal diffusivities demonstrated that the vertical moisture distribution of the debris cover must be taken into consideration, with the diffusivity values being significantly lower in deeper layers.