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Medientyp:
E-Artikel
Titel:
Basal friction of Fleming Glacier, Antarctica – Part 2: Evolution from 2008 to 2015
Beteiligte:
Zhao, Chen;
Gladstone, Rupert M.;
Warner, Roland C.;
King, Matt A.;
Zwinger, Thomas;
Morlighem, Mathieu
Erschienen:
Copernicus GmbH, 2018
Erschienen in:
The Cryosphere, 12 (2018) 8, Seite 2653-2666
Sprache:
Englisch
DOI:
10.5194/tc-12-2653-2018
ISSN:
1994-0424
Entstehung:
Anmerkungen:
Beschreibung:
Abstract. The Wordie Ice Shelf–Fleming Glacier system in the southern AntarcticPeninsula has experienced a long-term retreat and disintegration of its iceshelf in the past 50 years. Increases in the glacier velocity and dynamicthinning have been observed over the past two decades, especially after 2008when only a small ice shelf remained at the Fleming Glacier front. It isimportant to know whether the substantial further speed-up and greatersurface draw-down of the glacier since 2008 is a direct response to oceanforcing, or driven by feedbacks within the grounded marine-based glaciersystem, or both. Recent observational studies have suggested the2008–2015 velocity change was due to the ungrounding of the Fleming Glacierfront. To explore the mechanisms underlying the recent changes, we use afull-Stokes ice sheet model to simulate the basal shear stress distributionof the Fleming system in 2008 and 2015. This study is part of the first highresolution modelling campaign of this system. Comparison of inversions forbasal shear stresses for 2008 and 2015 suggests the migration of thegrounding line ∼9 km upstream by 2015 from the 2008 ice front/groundingline positions, which virtually coincided with the 1996 grounding lineposition. This migration is consistent with the change in floating areadeduced from the calculated height above buoyancy in 2015. The retrogradesubmarine bed underneath the lowest part of the Fleming Glacier may havepromoted retreat of the grounding line. Grounding line retreat may also beenhanced by a feedback mechanism upstream of the grounding line by whichincreased basal lubrication due to increasing frictional heating enhancessliding and thinning. Improved knowledge of bed topography near the groundingline and further transient simulations with oceanic forcing are required toaccurately predict the future movement of the Fleming Glacier systemgrounding line and better understand its ice dynamics and future contributionto sea level.