Ice-shelf buttressing and the stability of marine ice sheets

Ice-shelf buttressing and the stability of marine-type ice sheets are investigated numerically. Buttressing effects are analysed for a situation where a stable grounding line is located on a bed sloping upwards in the direction of flow. Such grounding-line positions are known to be unconditionally u...

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Bibliographic Details
Published in:The cryosphere 2013-04, Vol.7 (2), p.647-655
Main Author: Gudmundsson, G. H
Format: Article
Language:English
Subjects:
Buttresses
Flux
Grounding
Ice sheets
Mathematical analysis
Mathematical models
Slopes
Stability
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Summary:Ice-shelf buttressing and the stability of marine-type ice sheets are investigated numerically. Buttressing effects are analysed for a situation where a stable grounding line is located on a bed sloping upwards in the direction of flow. Such grounding-line positions are known to be unconditionally unstable in the absence of transverse flow variations. It is shown that ice-shelf buttressing can restore stability under these conditions. Ice flux at the grounding line is, in general, not a monotonically increasing function of ice thickness. This, possibly at first somewhat counterintuitive result, is found to be fully consistent with recent theoretical work. Grounding lines on retrograde slopes are conditionally stable, and the stability regime is a non-trivial function of bed and ice-shelf geometry. The stability of grounding lines cannot be assessed from considerations of local bed slope only.
ISSN:1994-0424
1994-0416
1994-0424
1994-0416
DOI:10.5194/tc-7-647-2013