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Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law

Benn DI, Todd J, Luckman A, Bevan S, Chudley TR, Åström J, Zwinger T, Cook S, Christoffersen P (2023)

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Publication Type: Journal article

Publication year: 2023

Journal

Book Volume: 69

Pages Range: 2059-2074

Journal Issue: 278

DOI: 10.1017/jog.2023.81

Abstract

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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How to cite

APA:

Benn, D.I., Todd, J., Luckman, A., Bevan, S., Chudley, T.R., Åström, J.,... Christoffersen, P. (2023). Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law. Journal of Glaciology, 69(278), 2059-2074. https://doi.org/10.1017/jog.2023.81

MLA:

Benn, Douglas I., et al. "Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law." Journal of Glaciology 69.278 (2023): 2059-2074.

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