Recent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula

Friedl, Peter; Seehaus, Thorsten; Wendt, Anja; Braun, Matthias; Höppner, Kathrin

doi:10.5194/tc-12-1347-2018

Cited by 39 publications

(47 citation statements)

References 72 publications

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“…By assuming the ice front position to coincide with the 1996 grounding line, uncertainty about the bedrock depth at the ice front feeds into significant uncertainty in the total restraining force from ocean pressure. Regarding velocities, Friedl et al (2018) presented evidence that an acceleration phase occurred on the Fleming Glacier between January and April 2008, but the surface velocity data used in the current study were extracted from measurements in autumn 2007(Rignot et al, 2011b. This means the surface velocity data, which provide the target to be matched by the inversion, might not be consistent with the DEM data used here (acquired in January 2008).…”

Section: Sensitivity To Ice Front Position and Boundary Conditionmentioning

confidence: 88%

“…The black, yellow, and cyan solid lines represent surface speed contours of 100, 1000, and 1500 m yr −1 , respectively. Black dotted line is the 1996 grounding line position (Rignot et al, 2011a). we do not exclude the possibility of high basal friction spots caused by the pinning points located at the 1996 grounding line, which is also proposed by Friedl et al (2018). An accurate location of the ice front and grounding line is clearly important for inverse modelling of fast-flowing glaciers like the Fleming Glacier.…”

Section: Sensitivity To Ice Front Position and Boundary Conditionmentioning

confidence: 92%

“…Internal deformation is dependent on gravitational driving stress, englacial temperature, the development of anisotropic structure at the grain scale in polycrystalline ice (e.g. Gagliardini et al, 2009) and larger-scale weakening from fractures (Borstad et al, 2013). Basal sliding is dependent on the gravitational driving stress, bedrock topography and the basal slipperiness, which in turn is affected by the roughness of the bed, the presence of deformable till or subglacial hydrology.…”

Section: Introductionmentioning

confidence: 99%

“…The Fleming Glacier (FG) (Fig. 1b), the main tributary glacier that fed the WIS, has a current length of ∼ 80 km and is ∼ 10 km wide near the ice front (Friedl et al, 2018). This glacier has recently shown a rapid increase in surface-lowering rates (doubling near the ice front after 2008) (Zhao et al, 2017) and the largest velocity changes (> 500 m yr −1 near the ice front) across the whole Antarctic Ice Sheet over (Walker and Gardner, 2017.…”

Section: Introductionmentioning

confidence: 99%

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Basal friction of Fleming Glacier, Antarctica – Part 1: Sensitivity of inversion to temperature and bedrock uncertainty

et al. 2018

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Abstract. Many glaciers in the Antarctic Peninsula are now rapidly losing mass. Understanding of the dynamics of these fast-flowing glaciers, and their potential future behaviour, can be improved through ice sheet modelling studies. Inverse methods are commonly used in ice sheet models to infer the spatial distribution of a basal friction coefficient, which has a large effect on the basal velocity and ice deformation. Here we use the full-Stokes Elmer/Ice model to simulate the Wordie Ice Shelf-Fleming Glacier system in the southern Antarctic Peninsula. With an inverse method, we infer the pattern of the basal friction coefficient from surface velocities observed in 2008. We propose a multi-cycle spin-up scheme to reduce the influence of the assumed initial englacial temperature field on the final inversion. This is particularly important for glaciers like the Fleming Glacier, which have areas of strongly temperature-dependent deformational flow in the fast-flowing regions. Sensitivity tests using various bed elevation datasets, ice front positions and boundary conditions demonstrate the importance of highaccuracy ice thickness/bed geometry data and precise location of the ice front boundary.

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Section: Sensitivity To Ice Front Position and Boundary Conditionmentioning

confidence: 88%

Section: Sensitivity To Ice Front Position and Boundary Conditionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Basal friction of Fleming Glacier, Antarctica – Part 1: Sensitivity of inversion to temperature and bedrock uncertainty

et al. 2018

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“…3a and b), and basal velocity of the WIS-FG system for 2008 and 2015 using an inverse method to determine the basal friction coefficient, C, with the geometry and velocity data described above. Although low-resolution estimation of basal shear stress has been carried out for the whole Antarctic Ice Sheet (Fürst et al, 2015;Morlighem et al, 2013;Sergienko et al, 2014), this is the first application of inverse methods to estimate the basal friction pattern of the Fleming system at a high resolution and to use the full-Stokes equations.…”

Section: Comparison Of Basal Shear Stress and Driving Stress In 2008 mentioning

confidence: 99%

Basal friction of Fleming Glacier, Antarctica – Part 2: Evolution from 2008 to 2015

et al. 2018

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Abstract. The Wordie Ice Shelf–Fleming Glacier system in the southern Antarctic Peninsula has experienced a long-term retreat and disintegration of its ice shelf in the past 50 years. Increases in the glacier velocity and dynamic thinning have been observed over the past two decades, especially after 2008 when only a small ice shelf remained at the Fleming Glacier front. It is important to know whether the substantial further speed-up and greater surface draw-down of the glacier since 2008 is a direct response to ocean forcing, or driven by feedbacks within the grounded marine-based glacier system, or both. Recent observational studies have suggested the 2008–2015 velocity change was due to the ungrounding of the Fleming Glacier front. To explore the mechanisms underlying the recent changes, we use a full-Stokes ice sheet model to simulate the basal shear stress distribution of the Fleming system in 2008 and 2015. This study is part of the first high resolution modelling campaign of this system. Comparison of inversions for basal shear stresses for 2008 and 2015 suggests the migration of the grounding line ∼9 km upstream by 2015 from the 2008 ice front/grounding line positions, which virtually coincided with the 1996 grounding line position. This migration is consistent with the change in floating area deduced from the calculated height above buoyancy in 2015. The retrograde submarine bed underneath the lowest part of the Fleming Glacier may have promoted retreat of the grounding line. Grounding line retreat may also be enhanced by a feedback mechanism upstream of the grounding line by which increased basal lubrication due to increasing frictional heating enhances sliding and thinning. Improved knowledge of bed topography near the grounding line and further transient simulations with oceanic forcing are required to accurately predict the future movement of the Fleming Glacier system grounding line and better understand its ice dynamics and future contribution to sea level.

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Antarctic ecosystem responses following ice‐shelf collapse and iceberg calving: Science review and future research

Ingels

Aronson

Smith

et al. 2020

WIREs Climate Change

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The calving of A‐68, the 5,800‐km2, 1‐trillion‐ton iceberg shed from the Larsen C Ice Shelf in July 2017, is one of over 10 significant ice‐shelf loss events in the past few decades resulting from rapid warming around the Antarctic Peninsula. The rapid thinning, retreat, and collapse of ice shelves along the Antarctic Peninsula are harbingers of warming effects around the entire continent. Ice shelves cover more than 1.5 million km2 and fringe 75% of Antarctica's coastline, delineating the primary connections between the Antarctic continent, the continental ice, and the Southern Ocean. Changes in Antarctic ice shelves bring dramatic and large‐scale modifications to Southern Ocean ecosystems and continental ice movements, with global‐scale implications. The thinning and rate of future ice‐shelf demise is notoriously unpredictable, but models suggest increased shelf‐melt and calving will become more common. To date, little is known about sub‐ice‐shelf ecosystems, and our understanding of ecosystem change following collapse and calving is predominantly based on responsive science once collapses have occurred. In this review, we outline what is known about (a) ice‐shelf melt, volume loss, retreat, and calving, (b) ice‐shelf‐associated ecosystems through sub‐ice, sediment‐core, and pre‐collapse and post‐collapse studies, and (c) ecological responses in pelagic, sympagic, and benthic ecosystems. We then discuss major knowledge gaps and how science might address these gaps. This article is categorized under: Climate, Ecology, and Conservation > Modeling Species and Community Interactions

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Recent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula

Abstract: Abstract. The Antarctic Peninsula is one of the world's regions most affected by climate change. Several ice shelves have retreated, thinned or completely disintegrated during recent decades, leading to acceleration and increased

Cited by 39 publications

References 72 publications

Basal friction of Fleming Glacier, Antarctica – Part 1: Sensitivity of inversion to temperature and bedrock uncertainty

Basal friction of Fleming Glacier, Antarctica – Part 1: Sensitivity of inversion to temperature and bedrock uncertainty

Basal friction of Fleming Glacier, Antarctica – Part 2: Evolution from 2008 to 2015

Antarctic ecosystem responses following ice‐shelf collapse and iceberg calving: Science review and future research

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