Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations

Benn, Douglas I.; Åström, Jan; Zwinger, Thomas; Todd, Joe; Nick, F. M.; Cook, Sue; Hulton, Nick; Luckman, Adrian

doi:10.1017/jog.2017.41

Cited by 106 publications

(174 citation statements)

References 50 publications

Supporting

Mentioning

158

Contrasting

Order By: Relevance

“…Benn et al (2017) compared HiDEM calving for specified undercuttings of different sizes and showed that calving magnitude increases with undercutting size. For small undercuttings, calving simply removes part of the overhang, but for large undercuttings calving removes all of the overhang plus additional ice.…”

Section: Calving Modelmentioning

confidence: 99%

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

et al. 2018

Self Cite

View full text Add to dashboard Cite

Abstract. In this paper, we study the effects of basal friction, sub-aqueous undercutting and glacier geometry on the calving process by combining six different models in an offlinecoupled workflow: a continuum-mechanical ice flow model (Elmer/Ice), a climatic mass balance model, a simple subglacial hydrology model, a plume model, an undercutting model and a discrete particle model to investigate fracture dynamics (Helsinki Discrete Element Model, HiDEM). We demonstrate the feasibility of reproducing the observed calving retreat at the front of Kronebreen, a tidewater glacier in Svalbard, during a melt season by using the output from the first five models as input to HiDEM. Basal sliding and glacier motion are addressed using Elmer/Ice, while calving is modelled by HiDEM. A hydrology model calculates subglacial drainage paths and indicates two main outlets with different discharges. Depending on the discharge, the plume model computes frontal melt rates, which are iteratively projected to the actual front of the glacier at subglacial discharge locations. This produces undercutting of different sizes, as melt is concentrated close to the surface for high discharge and is more diffuse for low discharge. By testing different configurations, we show that undercutting plays a key role in glacier retreat and is necessary to reproduce observed retreat in the vicinity of the discharge locations during the melting season. Calving rates are also influenced by basal friction, through its effects on near-terminus strain rates and ice velocity.

show abstract

Section: Calving Modelmentioning

confidence: 99%

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

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…If calving events are consistently smaller than the cavity, long-term frontal ablation rates will simply be determined by the submarine melt rate. On the other hand, stress migration effects may trigger calving events larger than the submarine cavity, in which case longterm frontal ablation rates will be greater than the submarine melt rate [5,6]. In addition, localized melt-undercutting may encourage calving of other parts of the glacier front.…”

Section: Processes Of Frontal Ablationmentioning

confidence: 99%

“…This snapshot shows the propagation of narrow fractures upward from the centres of the concentration in tensile stress at the base. Modified from Benn et al [5] plumes and the effects of ice mélange. When applied to Store Glacier, the model impressively replicates seasonal fluctuations of the glacier front without the need for model tuning [30].…”

Section: Modellingmentioning

confidence: 99%

“…Melting of the submerged portion of an ice front can trigger calving events, which might be several times larger than the original melted cavity [5,6]. In addition, frontal ablation is not simply a passive process of ice removal from glacier fronts.…”

Section: Introductionmentioning

confidence: 99%

“…Major advances have been made in observations of ice dynamics, fjord-water characteristics, processes and patterns of submarine melting, and the physics of iceberg calving [9]. The increasing richness of the observational record has been closely matched by rapid progress in numerical modelling capability [5,[10][11][12][13]. Straneo et al [9] highlighted three priorities for future research: (1) process studies targeting specific dynamic regimes, (2) sustained observations of key localities, and (3) synthesis of the results into improved process models and parameterizations.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Glacier Calving in Greenland

Benn

Cowton

Todd

et al. 2017

Curr Clim Change Rep

Self Cite

View full text Add to dashboard Cite

In combination, the breakaway of icebergs (calving) and submarine melting at marine-terminating glaciers account for between one third and one half of the mass annually discharged from the Greenland Ice Sheet into the ocean. These ice losses are increasing due to glacier acceleration and retreat, largely in response to increased heat flux from the oceans. Behaviour of Greenland's marine-terminating ('tidewater') glaciers is strongly influenced by fjord bathymetry, particularly the presence of 'pinning points' (narrow or shallow parts of fjords that encourage stability) and overdeepened basins (that encourage rapid retreat). Despite the importance of calving and submarine melting and significant advances in monitoring and understanding key processes, it is not yet possible to predict the tidewater glacier response to climatic and oceanic forcing with any confidence. The simple calving laws required for ice-sheet models do not adequately represent the complexity of calving processes. New detailed process models, however, are increasing our understanding of the key processes and are guiding the design of improved calving laws. There is thus some prospect of reaching the elusive goal of accurately predicting future tidewater glacier behaviour and associated rates of sea-level rise.

show abstract

A Full‐Stokes 3‐D Calving Model Applied to a Large Greenlandic Glacier

et al. 2018

Self Cite

View full text Add to dashboard Cite

Iceberg calving accounts for around half of all mass loss from both the Greenland and Antarctic ice sheets. The diverse nature of calving and its complex links to both internal dynamics and climate make it challenging to incorporate into models of glaciers and ice sheets. Here we present results from a new open‐source 3‐D full‐Stokes calving model developed in Elmer/Ice. The calving model implements the crevasse depth criterion, which states that calving occurs when surface and basal crevasses penetrate the full thickness of the glacier. The model also implements a new 3‐D rediscretization approach and a time‐evolution scheme which allow the calving front to evolve realistically through time. We test the model in an application to Store Glacier, one of the largest outlet glaciers in West Greenland, and find that it realistically simulates the seasonal advance and retreat when two principal environmental forcings are applied. These forcings are (1) submarine melting in distributed and concentrated forms and (2) ice mélange buttressing. We find that ice mélange buttressing is primarily responsible for Store Glacier's seasonal advance and retreat. Distributed submarine melting prevents the glacier from forming a permanent floating tongue, while concentrated plume melting has a disproportionately large and potentially destabilizing effect on the calving front position. Our results also highlight the importance of basal topography, which exerts a strong control on calving, explaining why Store Glacier has remained stable during a period when neighboring glaciers have undergone prolonged interannual retreat.

show abstract

Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations

Cited by 106 publications

References 50 publications

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

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

Glacier Calving in Greenland

A Full‐Stokes 3‐D Calving Model Applied to a Large Greenlandic Glacier

Contact Info

Product

Resources

About