EGU21-8460
https://doi.org/10.5194/egusphere-egu21-8460
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

3D modelling of Isbræ-type glaciers and temperate-zone processes 

Robert Law1, Poul Christoffersen1, Samuel Cook2, Emma MacKie3, and Marianne Haseloff4
Robert Law et al.
  • 1Scott Polar Research Institute, University of Cambridge
  • 2Institut des Géosciences de l'Environnement, Université Grenoble Alpes
  • 3Department of Geophysics, Stanford University
  • 4Department of Geography and Environmental Sciences, Northumbria University

The majority of Greenland’s outlet glaciers are Isbræ-type, with high driving stresses, steep surface slopes, flow through deep channels, and with a basal layer of temperate ice theorised to thicken towards the coastal margin. Understanding the formation processes and thermodynamic influence of this temperate ice is important as limited laboratory testing indicates temperate ice has a viscosity 5-10 times lower than cold ice with no liquid phase. Furthermore, limited field data suggests lower rates of deformation within basal temperate ice than in the cold ice directly overlying it, which is presently unexplained. Here, we present preliminary results from a 3D finite-element model of an idealised Isbrae-type glacier built with Elmer/Ice, incorporating water-content-dependent ice viscosity, basal melting, and a parameterization of basal crevassing, and use it to investigate the formation and thermodynamic behaviour of temperate ice in response to varying bedforms and model parameters. We find that the observed decrease in strain in temperate ice close to the glacier base can be explained by a high strain area close to the cold-temperate transition zone. We further compare our model results to temperate ice variability observed at Sermeq Kujalleq (Store Glacier) to determine key temperate ice parameters requiring further investigation. These results provide a more complete understanding of the heterogeneous ice deformation behind the fast movement of Greenland’s Isbræ-type glaciers and can therefore help to improve predictions of future glacier flow.

How to cite: Law, R., Christoffersen, P., Cook, S., MacKie, E., and Haseloff, M.: 3D modelling of Isbræ-type glaciers and temperate-zone processes , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8460, https://doi.org/10.5194/egusphere-egu21-8460, 2021.

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