The Cryosphere Discuss., 7, 4407-4442, 2013
www.the-cryosphere-discuss.net/7/4407/2013/
doi:10.5194/tcd-7-4407-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper is under review for the journal The Cryosphere (TC).
Modelling environmental influences on calving at Helheim Glacier, East Greenland
S. Cook1,2, I. C. Rutt1, T. Murray1, A. Luckman1, N. Selmes1, A. Goldsack1, and T. Zwinger3
1Glaciology Group, Geography Department, Swansea University, Swansea, SA2 8PP, UK
2Department of Geology, University Centre in Svalbard (UNIS), Pb. 156, 9171 Longyearbyen, Norway
3CSC – IT Center for Science Ltd., P.O. Box 405, FI-02101 Espoo, Finland

Abstract. Calving is an important mass-loss process for many glaciers worldwide, and has been assumed to respond to a variety of environmental influences. We present a grounded, flowline tidewater glacier model, using a physically realistic calving mechanism, which is applied to Helheim Glacier, East Greenland. By qualitatively examining both modelled size and frequency of calving events, and the subsequent dynamic response, the model is found to produce a realistic representation of calving behaviour. Experiments use four environmental variables which have been suggested to affect calving rates: water depth in crevasses, basal water pressure, undercutting of the calving face by submarine melt and backstress from ice mélange. Of the four variables, only crevasse water depth and basal water pressure were found to have a significant effect on terminus behaviour when applied at a realistic magnitude. These results are in contrast to previous modelling studies, which have suggested that ocean temperatures could strongly influence the calving front. The results raise the possibility that Greenland outlet glaciers could respond more strongly than previously thought to the recent trend of increased surface melt observed in Greenland, as surface ablation can strongly affect water depth in crevasses and water pressure at the glacier bed.

Citation: Cook, S., Rutt, I. C., Murray, T., Luckman, A., Selmes, N., Goldsack, A., and Zwinger, T.: Modelling environmental influences on calving at Helheim Glacier, East Greenland, The Cryosphere Discuss., 7, 4407-4442, doi:10.5194/tcd-7-4407-2013, 2013.
 
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