Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law
In: Journal of Glaciology, , S. 1-16
Online
academicJournal
Zugriff:
We investigate the physical basis of the crevasse-depth (CD) calving law by analysing relationships between glaciological stresses and calving behaviour at Sermeq Kujalleq (Store Glacier), Greenland. Our observations and model simulations show that the glacier has a stable position defined by a compressive arch between lateral pinning points. Ice advance beyond the arch results in calving back to the stable position; conversely, if melt-undercutting forces the ice front behind the stable position, it readvances because ice velocities exceed subaqueous melt rates. This behaviour is typical of self-organising criticality, in which the stable ice-front position acts as an attractor between unstable super-critical and sub-critical regimes. This perspective provides strong support for a ‘position-law’ approach to modelling calving at Sermeq Kujalleq, because any calving ‘rate’ is simply a by-product of how quickly ice is delivered to the critical point. The CD calving law predicts ice-front position from the penetration of surface and basal crevasse fields, and accurately simulates super-critical calving back to the compressive arch and melt-driven calving into the sub-critical zone. The CD calving law reflects the glaciological controls on calving at Sermeq Kujalleq and exhibits considerable skill in simulating its mean position and seasonal fluctuations.
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Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law
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Autor/in / Beteiligte Person: | Benn, Douglas I. ; Todd, Joe ; Luckman, Adrian ; Bevan, Suzanne ; Chudley, Thomas R. ; Åström, Jan ; Zwinger, Thomas ; Cook, Samuel ; Christoffersen, Poul |
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Zeitschrift: | Journal of Glaciology, , S. 1-16 |
Veröffentlichung: | Cambridge University Press. |
Medientyp: | academicJournal |
ISSN: | 0022-1430 (print) ; 1727-5652 (print) |
DOI: | 10.1017/jog.2023.81 |
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