A three-dimensional calving model: numerical experiments on Johnsons Glacier, Livingston Island, Antarctica

Otero, Jaime; Navarro, Francisco; Martín, Carlos; Cuadrado, María Luisa; Corcuera, M. I.

doi:10.3189/002214310791968539

Cited by 63 publications

(75 citation statements)

References 67 publications

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“…The model is allowed to evolve through time, with calving applied according to the crevassedepth calving criterion proposed by Benn et al (2007b) and used in previous modelling studies (Nick et al, 2010;Otero et al, 2010;Cook et al, 2012). The criterion states that calving will occur where the surface crevasse field penetrates below sea level.…”

Section: Model Setupmentioning

confidence: 99%

Modelling environmental influences on calving at Helheim Glacier in eastern Greenland

et al. 2014

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Abstract.Calving is an important mass-loss process for many glaciers worldwide, and has been assumed to respond to a variety of environmental influences. We present a grounded, flowline tidewater glacier model using a physically-based calving mechanism, applied to Helheim Glacier, eastern Greenland. By qualitatively examining both modelled size and frequency of calving events, and the subsequent dynamic response, the model is found to realistically reproduce key aspects of observed calving behaviour. Experiments explore four environmental variables which have been suggested to affect calving rates: water depth in crevasses, basal water pressure, undercutting of the calving face by submarine melt and backstress from ice mélange. Of the four variables, only crevasse water depth and basal water pressure were found to have a significant effect on terminus behaviour when applied at a realistic magnitude. These results are in contrast to previous modelling studies, which have suggested that ocean temperatures could strongly influence the calving front. The results raise the possibility that Greenland outlet glaciers could respond to the recent trend of increased surface melt observed in Greenland more strongly than previously thought, as surface ablation can strongly affect water depth in crevasses and water pressure at the glacier bed.

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Section: Model Setupmentioning

confidence: 99%

Modelling environmental influences on calving at Helheim Glacier in eastern Greenland

et al. 2014

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“…The computation of the crevasse penetration depth is based on the work of Nye (1957), and depends on the equilibrium between longitudinal stretching (opening term) and cryostatic pressure (closing term). This so-called "crevasse depth" criterion has been applied to individual marine-terminated glaciers in Greenland and Antarctica, and enabled the successful reproduction of variations in the front (Nick et al, 2010;Otero et al, 2010;Nick et al, 2013;Cook et al, 2014). Although the model of Nick et al (2010) accounts for basal crevasse propagation, which improves the ability of a model to reproduce observed behaviour, it is based on an instantaneous stress balance combined with an empirical criterion for calving.…”

Section: Introductionmentioning

confidence: 99%

Combining damage and fracture mechanics to model calving

et al. 2014

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Abstract.Calving of icebergs is a major negative component of polar ice-sheet mass balance. Here we present a new calving model relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and the rapid propagation of crevasses when calving occurs. First, damage to the ice occurs over long timescales and enhances the viscous flow of ice. Then brittle fractures propagate downward, at very short timescales, when the ice body is considered as an elastic medium. The model was calibrated on Helheim Glacier, Southeast Greenland, a well-monitored glacier with fast-flowing outlet. This made it possible to identify sets of model parameters to enable a consistent response of the model and to produce a dynamic equilibrium in agreement with the observed stable position of the Helheim ice front between 1930 and today.

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“…We implement and test four different calving laws, namely the height-above-buoyancy criterion (HAB, Vieli et al, 2001), the 30 crevasse-depth calving law (CD, Otero et al, 2010;Benn et al, 2017), the eigencalving law (EC, Levermann et al, 2012) and von Mises tensile stress calving law (VM, Morlighem et al, 2016), and model calving front migration of nine tidewater glaciers of Greenland for which we have a good description of the bed topography . The glaciers of this study are three branches of Upernavik Isstrøm (UI), Helheim glacier, three sectors of Hayes glacier, Kjer, and Sverdrup glaciers ( Fig.…”

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confidence: 99%

Comparison of four calving laws to model Greenland outlet glaciers

Choi¹,

Morlighem²,

Wood³

et al. 2018

Preprint

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Abstract. Calving is an important mechanism that controls the dynamics of marine terminating glaciers of Greenland. Iceberg calving at the terminus affects the entire stress regime of outlet glaciers, which may lead to further retreat and ice flow acceleration. It is therefore critical to accurately parameterize calving in ice sheet models in order to improve the projections of ice sheet change over the coming decades and reduce the uncertainty in their contribution to sea level rise. Several calving laws have been proposed, but most of them have been applied only to a specific region and have not been tested on other 5 glaciers, while some others have only been implemented in one-dimensional flowline or vertical flowband models. Here, we test and compare several calving laws recently proposed in the literature using the Ice Sheet System Model (ISSM). We test these calving laws on nine tidewater glaciers of Greenland. We compare the modeled ice front evolution to the observed retreat from Landsat data collected over the past 10 years, and assess which calving law has better predictive abilities for each glacier.Overall, the von Mises tensile stress calving law is more satisfactory than other laws for simulating observed ice front retreat, 10 but new parameterizations that capture better the different modes of calving should be developed. Although the final positions of ice fronts are different for forecast simulations with different calving laws, our results confirm that ice front retreat highly depends on bed topography irrespective of the calving law employed. This study also confirms that calving dynamics needs to be plan-view or 3D in ice sheet models to account for complex bed topography and narrow fjords along the coast of Greenland.

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A three-dimensional calving model: numerical experiments on Johnsons Glacier, Livingston Island, Antarctica

Cited by 63 publications

References 67 publications

Modelling environmental influences on calving at Helheim Glacier in eastern Greenland

Modelling environmental influences on calving at Helheim Glacier in eastern Greenland

Combining damage and fracture mechanics to model calving

Comparison of four calving laws to model Greenland outlet glaciers

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