A global map of supraglacial debris cover and recent debris area changes
Abstract
The extent of supraglacial rock debris is both a first order indicator of the rock flux within a glacier system and an important term in glacier mass balance models where debris cover modulates the energy fluxes that reach the buried glacier ice surface. To date, no global debris cover inventory is available and most global models of glacier change do not include the effect of debris cover on mass balance. We have used Landsat data and glacier outlines from the Randolph Glacier Inventory v6.0 and PROMICE (Programme for Monitoring of the Greenland Ice Sheet) to generate a modern-date global inventory of debris cover at a spatial resolution of 30 m. For select locations around the Earth with high concentrations of glacier ice and suitable historical imagery, we have derived changes in debris-covered area. We present the heterogeneous pattern of debris cover on Earth which is the integrated signal from hundreds of years of rock debris accumulation and transportation through each glacier system. We further resolve this debris history by presenting recent changes in debris-covered area over the satellite era. Preliminary results from Southeast Alaska, USA, Baffin Island, Canada, Southeast Greenland, and the Eastern Himalaya, China all show an increase in debris-covered area over the past tens of years with heterogeneous rates of increase. This study provides a greater geomorphological understanding of glaciers, their surrounding environment and the flux of supraglacial debris at timescales of both hundreds and tens of years. These data also serve as an input dataset and/or an indicator pointing to locations where debris cover needs to be considered in glacier melt models.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C41B1207H
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0746 Lakes;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE