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

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 flow(1-3). This uncertainty arises largely from a lack of direct measurements of water flow characteristics at the be...

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Bibliographic Details
Published in:Nature Geoscience
Main Authors: Chandler, D. M., Wadham, J. L., Lis, G. P., Cowton, T., Sole, A., Bartholomew, I., Telling, J., Nienow, P., Bagshaw, E. B., Mair, D., Vinen, S., Hubbard, A.
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
MOTION
POLYTHERMAL VALLEY GLACIER
SURFACE
ACCELERATION
WATER
SWITZERLAND
VELOCITY
HYDROLOGY
DAROLLA
glacier
Greenland
Ice Sheet
Online Access:https://hdl.handle.net/1983/f3117b91-538e-45bc-bd6a-7b09301de5a7
https://research-information.bris.ac.uk/en/publications/f3117b91-538e-45bc-bd6a-7b09301de5a7
https://doi.org/10.1038/ngeo1737
http://www.nature.com/ngeo/journal/v6/n3/full/ngeo1737.html
Description
Summary: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 flow(1-3). 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 velocities(4-7) and on meltwater flux(8). 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.

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