The Cryosphere Discuss., 7, 921-941, 2013
www.the-cryosphere-discuss.net/7/921/2013/
doi:10.5194/tcd-7-921-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
A particle based simulation model for glacier dynamics
J. A. Åström1, T. I. Riikilä2, T. Tallinen2, T. Zwinger1, D. Benn3,4, J. C. Moore5,6,7, and J. Timonen2
1CSC – It-centre for science, P.O. Box 405, 02101, Esbo, Finland
2Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), 40014, Jyväskylä, Finland
3Department of Geology, University Centre in Svalbard, 9171 Longyearbyen, Norway
4School of Geography and Geosciences, University of St Andrews, Fife, KY16 8ST, UK
5State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing, China
6Arctic Centre, University of Lapland, PL122, 96100 Rovaniemi, Finland
7Department of Earth Sciences, Uppsala University, Villavägen 16, Uppsala, 75236, Sweden

Abstract. A particle-based computer simulation model was developed for investigating the dynamics of glaciers. In the current model, large ice bodies are made of discrete elastic particles which are bound together by massless and elastic beams. The beams can break which induces brittle behaviour. At loads below fracture, beams may also break and reform with small probabilities in order to incorporate slowly deforming viscous behaviour in the model. This model has the advantage that it can simulate important physical processes such as ice calving and fracturing in a more realistic way than traditional continuum models. Two simulations were performed: (1) calving of an ice block partially supported in water, which could represent a grounded marine glacier terminus, and (2) fracturing of an ice block on an inclined plane of varying basal friction, which could represent transition to fast flow or surging. For benchmarking purposes the deformation of an ice block on a slip-free surface was compared to that of a similar block simulated with a Finite Element full-Stokes continuum model. In spite of several simplifications, which include restriction to two-dimenions and simplified rheology for water, the model introduced was able to reproduce the size distributions of the icebergs and the debris observed in calving. The size distributions we produce may be approximated by universal scaling laws. On a moderate slope, a large ice block was stable as long as there was enough of friction against the substrate. This was a quiescent state. For a critical length of frictional contact global sliding began, and the model block disintegrated in a manner suggestive of a surging glacier. In this case the fragment size distribution produced was typical of a grinding process.

Citation: Åström, J. A., Riikilä, T. I., Tallinen, T., Zwinger, T., Benn, D., Moore, J. C., and Timonen, J.: A particle based simulation model for glacier dynamics, The Cryosphere Discuss., 7, 921-941, doi:10.5194/tcd-7-921-2013, 2013.
 
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