Thinning sea ice weakens buttressing force of iceberg mélange and promotes calving

Robel, Alexander

doi:10.1038/ncomms14596

Cited by 107 publications

(130 citation statements)

References 36 publications

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“…One approach to model the ice mélange is to adopt a discrete element model and represent the motion of each iceberg and sea‐ice floe. Robel () used such a model to estimate the stress at a moving boundary, which pushed iceberg particles connected together with bonds designed to represent sea‐ice properties. This model can be useful for representing quick motions such as jamming wave propagation through the mélange following a calving event, such as those observed at Jakobshavn Isbræ (Peters et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…One approach to model the ice m elange is to adopt a discrete element model and represent the motion of each iceberg and sea-ice floe. Robel (2017) used such a model to estimate the stress at a moving boundary, Key Points: A continuum model for simulating ice m elange in fjords is developed Icebergs are included within an existing sea-ice model by modifying rheology Examples of sea ice interacting with moving and grounded icebergs are successfully simulated…”

Section: Introductionmentioning

confidence: 99%

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A Model of Icebergs and Sea Ice in a Joint Continuum Framework

Vaňková

Holland

2017

JGR Oceans

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The ice mélange, a mixture of sea ice and icebergs, often present in front of outlet glaciers in Greenland or ice shelves in Antarctica, can have a profound effect on the dynamics of the ice‐ocean system. The current inability to numerically model the ice mélange motivates a new modeling approach proposed here. A continuum sea‐ice model is taken as a starting point and icebergs are represented as thick and compact pieces of sea ice held together by large tensile and shear strength, selectively introduced into the sea‐ice rheology. In order to modify the rheology correctly, an iceberg tracking procedure is implemented within a semi‐Lagrangian time‐stepping scheme, designed to exactly preserve iceberg shape through time. With the proposed treatment, sea ice and icebergs are considered a single fluid with spatially varying rheological properties. Mutual interactions are thus automatically included without the need for further parametrization. An important advantage of the presented framework for an ice mélange model is its potential to be easily included within sea‐ice components of existing climate models.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Model of Icebergs and Sea Ice in a Joint Continuum Framework

Vaňková

Holland

2017

JGR Oceans

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“…Narrower bays tend to form transverse features, like moraines and GZW, which form during periods of ice stabilization (Anderson, 1999;Alley et al, 2007;Dowdeswell et al, 2008;Dowdeswell and Vasquez, 2013;Batchelor and Dowdeswell, 2015). The width of the glacial valley has been suggested to play an important role for glacial flow (O'Neel et al, 2005;Joughin et al, 2008;Robel, 2017). Similarly, widths of icestream troughs, along with water depth, control ice flow by increasing the lateral resistance (Whillans and van deer Veen, 1997;Jamieson et al, 2012).…”

Section: Geometry Of Baysmentioning

confidence: 99%

Seafloor geomorphology of western Antarctic Peninsula bays: a signature of ice flow behaviour

Munoz

Wellner

2018

The Cryosphere

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Abstract. Glacial geomorphology is used in Antarctica to reconstruct ice advance during the Last Glacial Maximum and subsequent retreat across the continental shelf. Analogous geomorphic assemblages are found in glaciated fjords and are used to interpret the glacial history and glacial dynamics in those areas. In addition, understanding the distribution of submarine landforms in bays and the local controls exerted on ice flow can help improve numerical models by providing constraints through these drainage areas. We present multibeam swath bathymetry from several bays in the South Shetland Islands and the western Antarctic Peninsula. The submarine landforms are described and interpreted in detail. A schematic model was developed showing the features found in the bays: from glacial lineations and moraines in the inner bay to grounding zone wedges and drumlinoid features in the middle bay and streamlined features and meltwater channels in the outer bay areas. In addition, we analysed local variables in the bays and observed the following: (1) the number of landforms found in the bays scales to the size of the bay, but the geometry of the bays dictates the types of features that form; specifically, we observe a correlation between the bay width and the number of transverse features present in the bays. (2) The smaller seafloor features are present only in the smaller glacial systems, indicating that short-lived atmospheric and oceanographic fluctuations, responsible for the formation of these landforms, are only recorded in these smaller systems. (3) Meltwater channels are abundant on the seafloor, but some are subglacial, carved in bedrock, and some are modern erosional features, carved on soft sediment. Lastly, based on geomorphological evidence, we propose the features found in some of the proximal bay areas were formed during a recent glacial advance, likely the Little Ice Age.

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“…In view of the ice thickness uncertainty (ranging from 10 to 100 m) and hence bedrock depth around the grounding line, and given the possibility of increased additional buttressing force due to floating icebergs and ice mélange as indicated in many previous studies (e.g. Amundson et al, 2010;Krug et al, 2015;Robel, 2017;Todd and Christoffersen, 2014;Walter et al, 2017) and clearly seen in Fig. 1c, we vary the ocean pressure boundary condition by varying the sea level used to calculate ocean water pressure.…”

Section: Experiments Designmentioning

confidence: 99%

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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Thinning sea ice weakens buttressing force of iceberg mélange and promotes calving

Cited by 107 publications

References 36 publications

A Model of Icebergs and Sea Ice in a Joint Continuum Framework

A Model of Icebergs and Sea Ice in a Joint Continuum Framework

Seafloor geomorphology of western Antarctic Peninsula bays: a signature of ice flow behaviour

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

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