Evolution of the subglacial drainage system beneath the Greenland Ice Sheet revealed by tracers

D. M. Chandler, J. L. Wadham, G. P. Lis, Tom Cowton, A. Sole, I. Bartholomew, J. Telling, P. Nienow, E. B. Bagshaw, D. Mair, S. Vinen, A. Hubbard

Research output: Contribution to journalArticlepeer-review

185 Citations (Scopus)

Abstract

Predictions of the Greenland Ice Sheet?s response to climate change are limited in part by uncertainty in the coupling between meltwater lubrication of the ice-sheet bed and ice flow1, 2, 3. This uncertainty arises largely from a lack of direct measurements of water flow characteristics at the bed of the ice sheet. Previous work has been restricted to indirect observations based on seasonal and spatial variations in surface ice velocities4, 5, 6, 7 and on meltwater flux8. Here, we employ rhodamine and sulphur hexafluoride tracers, injected into the drainage system over three melt seasons, to observe subglacial drainage properties and evolution beneath the Greenland Ice Sheet, up to 57?km from the margin. Tracer results indicate evolution from a slow, inefficient drainage system to a fast, efficient channelized drainage system over the course of the melt season. Further inland, evolution to efficient drainage occurs later and more slowly. An efficient routing of water was established up to 41?km or more from the margin, where the ice is approximately 1?km thick. Overall, our findings support previous interpretations of drainage system characteristics, thereby validating the use of surface observations as a means of investigating basal processes.
Original languageEnglish
Pages (from-to)195-198
Number of pages4
JournalNature Geoscience
Volume6
Issue number3
DOIs
Publication statusPublished - 1 Mar 2013

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