Effects of undercutting and sliding on calving: a coupled approach
applied to Kronebreen, Svalbard

Vallot, Dorothée; Åström, Jan; Zwinger, Thomas; Pettersson, R.; Everett, Alistair; Benn, Doug; Luckman, Adrian; Pelt, Ward van; Nick, F. M.

doi:10.5194/tc-2017-166

Cited by 2 publications

(1 citation statement)

References 25 publications

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“…By allowing the 20 bonds between particles to break, the model is able to explicitly develop fractures, rather than representing fracturing by a parameterisation as in continuum approaches. Discrete element models have been used successfully to simulate calving behaviour at marine terminating glaciers (Bassis and Jacobs, 2013;Vallot et al, 2017), to examine causes behind changes in calving behaviour (Åström et al, 2014) and to investigate how fracture propagation is affected by other elements of the cryospheric system Vallot et al, 2017). 25…”

Section: Introductionmentioning

confidence: 99%

Modelled fracture and calving on the Totten Ice Shelf

Cook¹,

Åström²,

Zwinger³

et al. 2018

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Abstract. 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 Shelf 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 calving on the Totten IS 15 is controlled not only by locally produced fractures at the calving front, but is also influenced by basal fractures which are likely produced at the grounding line. Our model results show that regrounding points may be key areas of basal crevasse production, and can produce basal crevasses in both an along and across flow orientation. As well as affecting calving, along flow basal crevasses at the grounding line may be a possible precursor to basal channels. We use two additional models to examine the evolution of basal fractures as they advect downstream, demonstrating that both strain and ocean melt have the 20 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.

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Section: Introductionmentioning

confidence: 99%

Modelled fracture and calving on the Totten Ice Shelf

Cook¹,

Åström²,

Zwinger³

et al. 2018

Preprint

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Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities

et al. 2017

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Abstract. Subglacial hydrological processes at tidewater glaciers remain poorly understood due to the difficulty in obtaining direct measurements and lack of empirical verification for modelling approaches. Here, we investigate the subglacial hydrology of Kronebreen, a fast-flowing tidewater glacier in Svalbard during the 2014 melt season. We combine observations of borehole water pressure, supraglacial lake drainage, surface velocities and plume activity with modelled run-off and water routing to develop a conceptual model that thoroughly encapsulates subglacial drainage at a tidewater glacier. Simultaneous measurements suggest that an earlyseason episode of subglacial flushing took place during our observation period, and a stable efficient drainage system effectively transported subglacial water through the northern region of the glacier tongue. Drainage pathways through the central and southern regions of the glacier tongue were disrupted throughout the following melt season. Periodic plume activity at the terminus appears to be a signal for modulated subglacial pulsing, i.e. an internally driven storage and release of subglacial meltwater that operates independently of marine influences. This storage is a key control on ice flow in the 2014 melt season. Evidence from this work and previous studies strongly suggests that long-term changes in ice flow at Kronebreen are controlled by the location of efficient/inefficient drainage and the position of regions where water is stored and released.

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Effects of undercutting and sliding on calving: a coupled approach applied to Kronebreen, Svalbard

Cited by 2 publications

References 25 publications

Modelled fracture and calving on the Totten Ice Shelf

Modelled fracture and calving on the Totten Ice Shelf

Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities

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