A simple 2D model of supraglacial debris cover evolution
Abstract
Mountain glaciers around the world are covered by some amount of supraglacial debris which alters the glacier melt regime. As glaciers shrink, and permafrost thaws, valley walls previously supported by ice and frozen ground become subject to erosion and rock failure and therefore cause an increase of supraglacial rock deposition. Additionally, sustained negative mass balance favors an increase in englacial debris emergence. While the relative contribution of these two processes is not entirely understood, it has been assumed that debris cover is increasing in association with a warming climate. Change in debris cover extent measured in the Alaska Range, the Swiss Alps and the Nepalese Himalaya support this assumption and show an increase in the percentage of debris covered area. Here we present a simple empirical model for evolving 2D debris covered area using data that is (potentially) easy to obtain: a digital elevation model, satellite derived surface temperature, and geologic maps. We solve independently for valley wall sourced debris deposits and ablation-dominated medial moraine debris sourced both from valley wall detritus buried under accumulated ice and englacial bedrock plucking. Currently, model calibration is required for each rock unit surrounding a glacier. We will use the results from detailed analysis of individual glaciers to gauge the accuracy of more generalized, regional scale solutions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.C22A..06H
- Keywords:
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- 0776 CRYOSPHERE Glaciology;
- 0722 CRYOSPHERE Rock glaciers;
- 0798 CRYOSPHERE Modeling;
- 0758 CRYOSPHERE Remote sensing