Modelled fracture and calving on the Totten Ice Shelf
<p>The Totten Ice Shelf (IS) has a large drainage basin, much of which is grounded below sea level, leaving the glacier vulnerable to retreat through the marine ice sheet instability mechanism. The ice shelf has also been shown to be sensitive to changes in calving rate, as a very small re...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-07-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/12/2401/2018/tc-12-2401-2018.pdf |
| Summary: | <p>The Totten Ice Shelf (IS) has a large drainage basin,
much of which is grounded below sea level, leaving the glacier vulnerable to
retreat through the marine ice sheet instability mechanism. The ice shelf
has also been shown to be sensitive to changes in calving rate, as a very
small retreat of the calving front from its current position is predicted to
cause a change in flow at the grounding line. Therefore understanding the
processes behind calving on the Totten IS is key to predicting its future
sea level rise contribution. Here we use the Helsinki Discrete Element Model (HiDEM)
to show that not all of the fractures visible at the front of the
Totten IS are produced locally, but that the across-flow basal crevasses,
which are part of the distinctive cross-cutting fracture pattern, are
advected into the calving front area from upstream. A separate simulation of
the grounding line shows that re-grounding points may be key areas of basal
crevasse production, and can produce basal crevasses in both an along- and
across-flow orientation. The along-flow basal crevasses at the grounding
line may be a possible precursor to basal channels, while we suggest the
across-flow grounding-line fractures are the source of the across-flow
features observed at the calving front. We use two additional models to
simulate the evolution of basal fractures as they advect downstream,
demonstrating that both strain and ocean melt have the potential to deform
narrow fractures into the broad basal features observed near the calving
front. The wide range of factors which influence fracture patterns and
calving on this glacier will be a challenge for predicting its future mass loss.</p> |
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| ISSN: | 1994-0416 1994-0424 |