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www.the-cryosphere-discuss.net/5/431/2011/
doi:10.5194/tcd-5-431-2011
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A comparison of glacier melt on debris-covered glaciers in the northern and southern Caucasus
1Inst. of Meteorology and Geophysics, Univ. of Innsbruck, Innrain 52, 6020 Innsbruck, Austria
2Commission for Glaciology, Bavarian Academy of Sciences and Humanities, Alfons-Goppel Str. 11, 80539 Munich, Germany
3Geography Department, Ludwig-Maximilians-Univ., Luisenstr. 37, 80333 Munich, Germany
4Department of Cryolithology and Glaciology, Geographical Faculty, Moscow State University, Leninskiye Gory, 119992-Moscow, Russia
5Vakhushti Bagrationi State Institute of Geography, Tbilisi, Georgia
Abstract. The glacier coverage in the Caucasus Mountains underwent considerable changes during the last decades. Besides a reduction in glacier area which in some areas is comparable to area changes in the European Alps, also the concentration of supra-glacial debris increased on many glaciers. Only a few glaciers in the Caucasus are monitored on a regular basis, while for most areas no field measurements are available on a continuous basis. In this study the regional differences between the well studied Adyl-su basin on the northern slope of the Caucasus is compared with a similar basin in the South (Zopkhito basin). Special focus is laid on the effect of supra-glacial debris cover on the melt conditions during the ablation season. Systematic differences can be shown for the distribution and temporal increase of the debris cover on the glaciers. While in the Adyl-su basin an extensive debris cover on the glacier tongues is common, only some low lying glacier tongues in the Zopkhito basin show considerable supra-glacial debris. Also the temporal increase in debris cover is decidedly stronger in the North. Field experiments show that the thermal resistance of the debris cover is somewhat higher than in other glacerised regions in the world. A simple ablation model which includes the effect of the debris cover on ice melt indicates considerably stronger melt rates in the northern basin, despite the much more widespread debris distribution. This is due to the different meteorological conditions with more frequent cloud cover and precipitation in the South. Still ablation is strongly influenced in both basins by the occurrence of supra-glacial debris cover, reducing the total amount of melt on the glacier by about 20%. Especially in the lower tongue areas this effect mitigates the area loss of the glaciers considerably.
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Notice on Discussion StatusCitation: Lambrecht, A., Mayer, C., Hagg, W., Popovnin, V., Rezepkin, A., Lomidze, N., and Svanadze, D.: A comparison of glacier melt on debris-covered glaciers in the northern and southern Caucasus, The Cryosphere Discuss., 5, 431-459, doi:10.5194/tcd-5-431-2011, 2011. Bibtex EndNote Reference Manager XML
