Marine glaciers, ice shelves & calving

What controls the grounding-line stabilisation?
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Marine ice sheet instability due to a reversing slope bed. Enhanced melting at the bottom of the ice shelf due to Circumpolar deep water circulation, this causes thinning and decrease buttressing of the ice shelf which leads to the acceleration of the ice streams and the retreat of the grounding line into the glacier's trunk. The glacier trunk is situated in a deep subglacial trough.
Controls on the calving lossFlow acceleration and ice thinning. Increase calving fluxes, calving front retreats and increases the rate of ice delivered to the point.What makes a good receipe for calving failure?Large velocity gradients and steep crevasse penetration. Width is also very important tidewater glaciers and ice shelves at fjords and embayment widenings will result in huge calving losses (Benn, Wassen and Mottram, 2007)Where is ice loss seen at in Greenland and Antarctic Ice Sheets?In Greenland it is at all latitudes and on the grounding lines of Antarctica. Most profound changes are at the ocean margins (Pritchard et al., 2009)Where is dynamic thinning occurring in Greenland?Strong thinning is seen on the SE & NW ice sheet margins. Negative mass balance due to the discharge of tidewater glaciers (Pritchard et al., 2009)What caused the surge of the variegated glacier in 1964-65Cool spring- delayed the availability of the surface waters- terminationCause 1982-83 variegated surge?Changes in the subglacial hydraulic system. Switch to efficient discrete basal hydraulic system during the quiescent phase to a distributed one linked to the cavities overlying bedWhat triggers a jokulhlaupsThe sudden changes in the discharge/ pressure gradient in a subglacial drainage system beneath the ice dams due to surface melting which causes the unstable growth of conduitsWhat are the mechanisms of a glacier surgeHigh basal pressures deformation of till disruption of drainage system and basal sliding