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The Cryosphere Discuss., 5, 2629-2663, 2011
www.the-cryosphere-discuss.net/5/2629/2011/ doi:10.5194/tcd-5-2629-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
Influence of surface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps
Alpine Cryosphere and Geomorphology (ACAG), Department of Geosciences, University of Fribourg, Fribourg, Switzerland
Abstract. Compared to lowland (polar) regions, permafrost in high mountain areas occurs in a large variety of surface and subsurface material and texture. This work presents an eight-year (2002–2010) data set of borehole temperatures for five different (sub-) surface materials from a high alpine permafrost area, Murtel-Corvatsch, Switzerland. The influence of the material on the thermal regime was investigated by borehole temperature data, the TTOP-concept and the apparent thermal diffusivity (ATD). The results show that during the last eight years material specific temperature changes were more significant than for all boreholes consistent, climate-induced temperature trends. At coarse blocky, ice-rich sites no changes in active layer depth were observed, whereas the bedrock and the fine-grained sites appear to be highly sensitive to changes in the microclimate. The results confirm that the presence and growth of ice as well as a thermally driven air-circulation within the subsurface are the key factors for the occurence and preservation of alpine permafrost.
Citation: Schneider, S., Hoelzle, M., and Hauck, C.: Influence of surface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps, The Cryosphere Discuss., 5, 2629-2663, doi:10.5194/tcd-5-2629-2011, 2011.