Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage.
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Authors
Tulaczyk, Slawek M
Mankoff, Kenneth D
Nicholls, Keith W
Publication Date
2022-03-08Journal Title
Proc Natl Acad Sci U S A
ISSN
0027-8424
Publisher
Proceedings of the National Academy of Sciences
Volume
119
Issue
10
Language
eng
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Young, T. J., Christoffersen, P., Bougamont, M., Tulaczyk, S. M., Hubbard, B., Mankoff, K. D., Nicholls, K. W., & et al. (2022). Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage.. Proc Natl Acad Sci U S A, 119 (10) https://doi.org/10.1073/pnas.2116036119
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.
Keywords
Climate change, Greenland, Ice Sheets, Glaciology, Radio Echo Sounding
Sponsorship
EU Horizon 2020
Funder references
Natural Environment Research Council (NE/K005871/1)
European Commission Horizon 2020 (H2020) ERC (3276207)
Identifiers
35193940, PMC8915971
External DOI: https://doi.org/10.1073/pnas.2116036119
This record's URL: https://www.repository.cam.ac.uk/handle/1810/335417
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc-nd/4.0/
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