Basal friction of Fleming Glacier, Antarctica – Part 2: evolution from 2008 to 2015
The Wordie Ice Shelf–Fleming Glacier system inthe southern Antarctic Peninsula has experienced a longtermretreat and disintegration of its ice shelf in the past50 years. Increases in the glacier velocity and dynamic thinninghave been observed over the past two decades, especiallyafter 2008 when only...
| Published in: | The Cryosphere |
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| Main Authors: | , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus GmbH
2018
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| Subjects: | |
| Online Access: | https://eprints.utas.edu.au/28027/ https://eprints.utas.edu.au/28027/1/tc-12-2653-2018.pdf https://eprints.utas.edu.au/28027/2/127893%20-%20Basal%20friction%20of%20Fleming%20Glacier%20Antarctica%20Part%202.pdf |
| Summary: | The Wordie Ice Shelf–Fleming Glacier system inthe southern Antarctic Peninsula has experienced a longtermretreat and disintegration of its ice shelf in the past50 years. Increases in the glacier velocity and dynamic thinninghave been observed over the past two decades, especiallyafter 2008 when only a small ice shelf remained atthe Fleming Glacier front. It is important to know whetherthe substantial further speed-up and greater surface drawdownof the glacier since 2008 is a direct response to oceanforcing, or driven by feedbacks within the grounded marinebasedglacier system, or both. Recent observational studieshave suggested the 2008–2015 velocity change was due tothe ungrounding of the Fleming Glacier front. To explore themechanisms underlying the recent changes, we use a full-Stokes ice sheet model to simulate the basal shear stressdistribution of the Fleming system in 2008 and 2015. Thisstudy is part of the first high resolution modelling campaignof this system. Comparison of inversions for basalshear stresses for 2008 and 2015 suggests the migrationof the grounding line ~ 9 km upstream by 2015 from the2008 ice front/grounding line positions, which virtually coincidedwith the 1996 grounding line position. This migrationis consistent with the change in floating area deducedfrom the calculated height above buoyancy in 2015. Theretrograde submarine bed underneath the lowest part of theFleming Glacier may have promoted retreat of the groundingline. Grounding line retreat may also be enhanced by a feedbackmechanism upstream of the grounding line by whichincreased basal lubrication due to increasing frictional heatingenhances sliding and thinning. Improved knowledge ofbed topography near the grounding line and further transientsimulations with oceanic forcing are required to accuratelypredict the future movement of the Fleming Glacier systemgrounding line and better understand its ice dynamics andfuture contribution to sea level. |
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