Abstract
Subglacial hydrologic systems regulate ice sheet flow, causing acceleration or deceleration, depending on hydraulic efficiency and the rate at which surface meltwater is delivered to the bed. Because these systems are rarely observed, ice sheet basal drainage represents a poorly integrated and uncertain component of models used to predict sea level changes. Here, we report radar-derived basal melt rates and unexpectedly warm subglacial conditions beneath a large Greenlandic outlet glacier. The basal melt rates averaged 14 mm ⋅d-1 over 4 months, peaking at 57 mm ⋅d-1 when basal water temperature reached +0.88∘C in a nearby borehole. We attribute both observations to the conversion of potential energy of surface water to heat in the basal drainage system, which peaked during a period of rainfall and intense surface melting. Our findings reveal limitations in the theory of channel formation, and we show that viscous dissipation far surpasses other basal heat sources, even in a distributed, high-pressure system.
Original language | English |
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Article number | e2116036119 |
Number of pages | 8 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 119 |
Issue number | 10 |
Early online date | 22 Feb 2022 |
DOIs | |
Publication status | Published - 8 Mar 2022 |
Keywords
- Climate change
- Radio echo sounding
- Greenland
- Glaciology
- Ice sheets
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Dive into the research topics of 'Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage'. Together they form a unique fingerprint.Datasets
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Basal melt rates derived from radar measurements at Sermeq Kujalleq (Store Glacier) in Greenland
Young, T. (Contributor) & Christoffersen, P. (Contributor), University of Cambridge, 23 Feb 2022
DOI: 10.17863/cam.80852
Dataset
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Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage (dataset)
Young, T. J. (Creator), Christoffersen, P. (Creator), Bougamont, M. (Creator), Tulaczyk, S. M. (Creator), Hubbard, B. (Creator), Mankoff, K. D. (Creator), Nicholls, K. W. (Creator) & Stewart, C. L. (Creator), British Geological Survey, 22 Feb 2022
Dataset