Thermal Properties of a Supraglacial Debris Layer with Respect to Lithology and Grain Size |
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Authors: | Martin Juen Christoph Mayer Astrid Lambrecht Anna Wirbel Ulrich Kueppers |
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Institution: | 1. Commission for Geodesy and Glaciology, Bavarian Academy of Sciences, , D‐80539 Munich, Germany;2. Institute of Meteorology and Geophysics, University of Innsbruck, , A‐6020 Innsbruck, Austria;3. Earth and Environmental Sciences, Ludwig‐Maximilians‐University Munich, , D‐80333 Munich, Germany |
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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. |
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Keywords: | supraglacial debris ablation debris‐covered glaciers thermal conductivity thermal diffusivity Vernagtferner Austria |
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