Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage

Funding: This research was funded by the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant 683043). P.C., M.B., and B.H. were supported by the Natural Environment Research Council (Grants NE/K005871/1 and NE/K006126). B.H. was also supported by...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences
Main Authors: Young, Tun Jan, Christoffersen, Poul, Bougamont, Marion, Tulaczyk, Slawek M, Hubbard, Bryn, Mankoff, Kenneth D, Nicholls, Keith W, Stewart, Craig L
Other Authors: University of St Andrews. School of Geography & Sustainable Development
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
Climate change
Radio echo sounding
Greenland
Glaciology
Ice sheets
GB Physical geography
GE Environmental Sciences
DAS
SDG 13 - Climate Action
MCC
GB
GE
glacier
greenlandic
Ice Sheet
Online Access:http://hdl.handle.net/10023/27371
https://doi.org/10.1073/pnas.2116036119
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Summary:Funding: This research was funded by the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant 683043). P.C., M.B., and B.H. were supported by the Natural Environment Research Council (Grants NE/K005871/1 and NE/K006126). B.H. was also supported by the Higher Education Funding Council for Wales and an Aberystwyth University Capital Equipment Grant. 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. Publisher PDF Peer reviewed

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