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dc.contributor.authorBenedek, CLen
dc.contributor.authorWillis, Ianen
dc.date.accessioned2021-04-06T23:30:49Z
dc.date.available2021-04-06T23:30:49Z
dc.date.issued2021-03-31en
dc.identifier.issn1994-0416
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/319511
dc.description.abstractAbstract. Surface lakes on the Greenland Ice Sheet play a key role in its surface mass balance, hydrology and biogeochemistry. They often drain rapidly in the summer via hydrofracture, which delivers lake water to the ice sheet base over timescales of hours to days and then can allow meltwater to reach the base for the rest of the summer. Rapid lake drainage, therefore, influences subglacial drainage evolution; water pressures; ice flow; biogeochemical activity; and ultimately the delivery of water, sediments and nutrients to the ocean. It has generally been assumed that rapid lake drainage events are confined to the summer, as this is typically when observations are made using satellite optical imagery. Here we develop a method to quantify backscatter changes in satellite radar imagery, which we use to document the drainage of six different lakes during three winters (2014/15, 2015/16 and 2016/17) in fast-flowing parts of the Greenland Ice Sheet. Analysis of optical imagery from before and after the three winters supports the radar-based evidence for winter lake drainage events and also provides estimates of lake drainage volumes, which range between 0.000046 ± 0.000017 and 0.0200 ± 0.002817 km3. For three of the events, optical imagery allows repeat photoclinometry (shape from shading) calculations to be made showing mean vertical collapse of the lake surfaces ranging between 1.21 ± 1.61 and 7.25 ± 1.61 m and drainage volumes of 0.002 ± 0.002968 to 0.044 ± 0.009858 km3. For one of these three, time-stamped ArcticDEM strips allow for DEM differencing, which demonstrates a mean collapse depth of 2.17 ± 0.28 m across the lake area. The findings show that lake drainage can occur in the winter in the absence of active surface melt and notable ice flow acceleration, which may have important implications for subglacial hydrology and biogeochemical processes.
dc.description.sponsorshipCorinne L. Benedek is funded by the Howard Research Studentship through Sidney Sussex College and the Cambridge Trust. Ian C. Willis was supported by a Cooperative Institute for Research in Environmental Sciences (CIRES) University of Colorado Boulder Visiting Sabbatical Fellowship
dc.publisherCopernicus GmbH
dc.rightsAttribution 4.0 International
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.titleWinter drainage of surface lakes on the Greenland Ice Sheet from Sentinel-1 SAR imageryen
dc.typeArticle
prism.endingPage1606
prism.issueIdentifier3en
prism.publicationDate2021en
prism.publicationNameCryosphereen
prism.startingPage1587
prism.volume15en
dc.identifier.doi10.17863/CAM.66632
dcterms.dateAccepted2021-02-04en
rioxxterms.versionofrecord10.5194/tc-15-1587-2021en
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2021-03-31en
dc.contributor.orcidWillis, Ian [0000-0002-0750-7088]
dc.identifier.eissn1994-0424
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idNERC (NE/T006234/1)


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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International