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Permanent fast flow versus cyclic surge behaviour: numerical simulations of the Austfonna ice cap, Svalbard
| Title: | Permanent fast flow versus cyclic surge behaviour: numerical simulations of the Austfonna ice cap, Svalbard |
| Authors: | Dunse, Thorben Browse this author | | Greve, Ralf Browse this author →KAKEN DB | | Schuler, Thomas Vikhamar Browse this author | | Hagen, Jon Ove Browse this author |
| Keywords: | Austfonna | | Ice cap | | Surge | | Oscillation | | Modelling |
| Issue Date: | 1-Apr-2011 |
| Publisher: | International Glaciological Society |
| Journal Title: | Journal of Glaciology |
| Volume: | 57 |
| Issue: | 202 |
| Start Page: | 247 |
| End Page: | 259 |
| Publisher DOI: | 10.3189/002214311796405979 |
| Abstract: | A large part of the ice flux within ice caps occurs through spatially limited fast-flowing units. Some of them permanently maintain fast flow, whereas others operate in an oscillatory mode, characterized by short-lived active phases followed by long quiescent phases. This surge-type behaviour results from intrinsic rather than external factors, thus complicating estimates of glacier response to climate change. Here we present numerical model results from Austfonna, an ice cap on Svalbard that comprises several surge-type basins. Previous studies have suggested a thermally controlled soft-bed surge mechanism for Svalbard. We systematically change the parameters that govern the nature of basal motion and thereby control the transition between permanent and oscillatory fast flow. Surge-type behaviour is realized by a relatively abrupt onset of basal sliding when basal temperatures approach the pressure-melting point and enhanced sliding of marine grounded ice. Irrespective of the dynamic regime, the absence of considerable volumes of temperate ice, both in the observed and simulated ice cap, indicates that fast flow is accomplished by basal motion over a temperate bed. Given an idealized present-day climate, the equilibrium ice-cap size varies significantly, depending on the chosen parameters. |
| Rights: | © 2011 International Glaciological Society |
| Relation: | http://www.igsoc.org/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/47983 |
| Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: Greve Ralf
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