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dc.contributor.authorGudlaugsson, Eythor
dc.contributor.authorHumbert, Angelika
dc.contributor.authorKleiner, Thomas
dc.contributor.authorKohler, Jack
dc.contributor.authorAndreassen, Karin
dc.date.accessioned2017-03-21T13:48:12Z
dc.date.available2017-03-21T13:48:12Z
dc.date.issued2016-04-05
dc.description.abstractAs ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and releases deformation energy that can raise the temperature locally. Recent studies of Antarctic subglacial lakes indicate that many lakes experience very fast and possibly episodic drainage, during which the lake size is rapidly reduced as water flows out. Questions that arise are what effect this would have on internal layers within the ice and whether such past drainage events could be inferred from isochrone structures downstream. Here, we study the effect of a subglacial lake on ice dynamics as well as the influence that such short timescale drainage would have on the internal layers of the ice. To this end, we use a full Stokes, polythermal ice flow model. An enthalpy-gradient method is used to account for the evolution of temperature and water content within the ice. We find that a rapid transition between slow-moving ice outside the lake, and full sliding over the lake, can release considerable amounts of deformational energy, with the potential to form a temperate layer at depth in the transition zone. In addition, we provide an explanation for a characteristic surface feature commonly seen at the edges of subglacial lakes, a hummocky surface depression in the transition zone between little to full sliding. We also conclude that rapid changes in the horizontal extent of subglacial lakes and slippery patches, compared to the average ice column velocity, can create a traveling wave at depth within the isochrone structure that transfers downstream with the advection of ice, thus indicating the possibility of detecting past drainage events with ice penetrating radar.en_US
dc.description.sponsorshipFunding for this work came from the Research Council of Norway (RCN), Statoil, Det Norske ASA and BG group, Norway (grant 200672), to the PetroMaks project “Glaciations in the Barents Sea area (GlaciBar)”, and from the Research School in Arctic Marine Geology and Geophysics (AMGG) at the University of Tromsø. This is also a contribution to the Centre of Excellence: Arctic Gas Hydrate, Environment and Climate (CAGE) funded by RCN (grant 223259). In addition, we would like to thank Nina Wilkens and Martin Rückamp for help with getting started with COMSOL, the Stallo support team for invaluable assistance, and Gwendolyn Leysinger Vieli, as well as one anonymous reviewer and the editor Robert Bingham for constructive reviews and comments that greatly improved the quality of the manuscript.en_US
dc.identifier.citationGudlaugsson E, Humbert A, Kleiner T, Kohler J, Andreassen K. The influence of a model subglacial lake on ice dynamics and internal layering. The Cryosphere. 2016;10(2):751-760en_US
dc.identifier.cristinIDFRIDAID 1348975
dc.identifier.doi10.5194/tc-10-751-2016
dc.identifier.issn1994-0416
dc.identifier.issn1994-0424
dc.identifier.urihttps://hdl.handle.net/10037/10802
dc.language.isoengen_US
dc.publisherEuropean Geoscience Unionen_US
dc.relation.ispartofGudlaugsson, E. (2015). Modelling the subglacial hydrology of the former Barents Sea Ice Sheet. (Doctoral thesis). <a href=https://hdl.handle.net/10037/25064>https://hdl.handle.net/10037/25064</a>
dc.relation.journalThe Cryosphere
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/PETROMAKS/200672/Norway/Glaciations in the Barents Sea area//en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGEen_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.subjectsubglacial lakeen_US
dc.subjectice dynamicsen_US
dc.subjectisochronesen_US
dc.subjectAntarcticaen_US
dc.subjectGreenlanden_US
dc.subjectice-sheet interioren_US
dc.subjectthermal momentumen_US
dc.subjectCOMSOLen_US
dc.subjectice temperatureen_US
dc.titleThe influence of a model subglacial lake on ice dynamics and internal layeringen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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