Abstract
Abstract. 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.
Highlights
A marine-type ice sheet is an ice sheet that rests on a bed located below sea level
In addition to being a marine-type ice sheet, West Antarctic ice sheet (WAIS) is mostly located on a retrograde bed, i.e. a bed that generally slopes towards the centre of the ice sheet
The following main bulk of the paper focuses on an analysis of the stress regime along the grounding line, and on the role of ice-shelf buttressing in affecting the state of stress, ice flux, and the stability regime of marine ice sheets
Summary
A marine-type ice sheet is an ice sheet that rests on a bed located below sea level. Today the prime example of such an ice sheet is the West Antarctic ice sheet (WAIS). Weertman, 1974; Thomas and Bentley, 1978; Hindmarsh, 1993, 1996; Wilchinsky, 2001, 2009; Schoof, 2007a,b, 2011; Robison et al, 2010) it is generally accepted that grounding lines of marine ice sheets located on retrograde beds are unconditionally unstable, provided that the flow field does not vary in transverse direction. In the more general geometrical setting where flow and stress fields can vary in both horizontal directions, marine-type ice sheets resting on retrograde slopes are conditionally unstable (Gudmundsson et al, 2012). The following main bulk of the paper focuses on an analysis of the stress regime along the grounding line, and on the role of ice-shelf buttressing in affecting the state of stress, ice flux, and the stability regime of marine ice sheets
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
