Brief communication: Thinning of debris-covered and debris-free glaciers in a warming climate
Recent geodetic mass-balance measurements reveal similar thinning rates on glaciers with or without debris cover in the Himalaya–Karakoram region. This comes as a surprise as a thick debris cover reduces the surface melting significantly due to its insulating effects. Here we present arguments, supp...
Published in: | The Cryosphere |
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Main Author: | |
Format: | Article in Journal/Newspaper |
Language: | English |
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Copernicus Publications
2017
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Online Access: | https://doi.org/10.5194/tc-11-133-2017 https://noa.gwlb.de/receive/cop_mods_00042779 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042399/tc-11-133-2017.pdf https://tc.copernicus.org/articles/11/133/2017/tc-11-133-2017.pdf |
Summary: | Recent geodetic mass-balance measurements reveal similar thinning rates on glaciers with or without debris cover in the Himalaya–Karakoram region. This comes as a surprise as a thick debris cover reduces the surface melting significantly due to its insulating effects. Here we present arguments, supported by results from numerical flowline model simulations of idealised glaciers, that a competition between the changes in the surface mass-balance forcing and that of the emergence/submergence velocities can lead to similar thinning rates on these two types of glaciers. As the climate starts warming, the thinning rate on a debris-covered glacier is initially smaller than that on a similar debris-free glacier. Subsequently, the rate on the debris-covered glacier becomes comparable to and then larger than that on the debris-free one. The time evolution of glacier-averaged thinning rates after an initial warming is strongly controlled by the time variation of the corresponding emergence velocity profile. |
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