Elmer/Ice News

Elmer/Ice at EGU General Assembly 2023

Elmer/Ice is prominently present at this year's EGU General Assembly with a dedicated splinter meeting wherein the 10th Elmer/Ice User Meeting will take place. Please, find instructions how to participate the User Meeting (we also try to organise a Zoom link for streaming) on the corresponding Wiki-page.

Using the search on the programme page of EGU, we identify the following talks that seem to involve Elmer/Ice in some wider connection (in chronological order; click on links for details)

The EuroHPC Center of Excellence for Exascale in Solid Earth  
Arnau Folch, Josep DelaPuente, Antonio Costa, Benedikt Halldórson, Jose Gracia, Piero Lanucara, Michael Bader, Alice-Agnes Gabriel, Jorge Macías, Finn Lovholt, Vadim Montellier, Alexandre Fournier, Erwan Raffin, Thomas Zwinger, Clea Denamiel, Boris Kaus, and Laetitia le Pourhiet
Mon, 24 Apr, 08:35–08:45  Room 0.16

Numerical modelling of rapidly-rising glacier outburst floods  
Tómas Jóhannesson, Thomas Zwinger, Peter Råback, and Juha Ruokolainen
Mon, 24 Apr, 11:45–11:55  Room L3

Seasonal and inter annual effects of meltwater runoff on ice dynamics in Northeast Greenland  
Ilaria Tabone, Johannes J. Fürst, and Thomas Mölg
Mon, 24 Apr, 14:00–15:45  Hall X5 X5.237

A periodic visco-elastic model for crevasses propagation in marine ice shelves  
Maryam Zarrinderakht, Thomas Zwinger, and Christian Schoof
Mon, 24 Apr, 14:15–14:25  Room L3

Effect of mesh resolution on accurate grounding line definition using 2D finite element software, Elmer/ice  
Su-jeong Lim and Byung-Dal So
Mon, 24 Apr, 14:00–15:45  Hall X5 X5.222

A 3D glacier dynamics-line plume model to estimate the frontal ablation of Hansbreen, Svalbard  
José Manuel Muñoz Hermosilla, Eva De Andrés, Kaian Shahateet, Jaime Otero, and Francisco J. Navarro
Tue, 25 Apr, 11:15–11:25  Room L3

Constraining the overall future projection of Upernavik Isstrøm by observations  
Eliot Jager, Fabien Gillet-Chaulet, Nicolas Champollion, and Romain Millan
Tue, 25 Apr, 12:05–12:15  Room L3

Modelling the kinematic evolution of valley-scale folding in surge-type glaciers using Elmer/Ice  
Erik Young, Gwenn Flowers, Hester Jiskoot, and Daniel Gibson
Tue, 25 Apr, 16:15–16:25  Room L2

Large-amplitude perturbation experiments to assess the unstable behaviour of AIS in the near future  
Benoit Urruty, Olivier Gagliardini, Fabien Gillet-Chaulet, Gael Durand, and Mondher Chekki
Tue, 25 Apr, 17:25–17:35  Room L2

On the effect of damage on the recent changes in the Amundsen Sea Sector  
Cyrille Mosbeux, Nicolas Jourdain, Olivier Gagliardini, Peter Råback, and Adrien Gilbert
Tue, 25 Apr, 17:45–17:55  Room L2

Modelling the three-dimensional stratigraphy of an ice rise  
Clara Henry, Reinhard Drews, Clemens Schannwell, Vjeran Višnjević, Inka Koch, Heiko Spiegel, Leah Muhle, Olaf Eisen, Daniela Jansen, Steven Franke, and Paul Bons
Wed, 26 Apr, 09:20–09:30  Room 1.61/62

Elmer/Ice results on the CalvingMIPintercomparison project using a level-set function  
Cruz Garcia-Molina, Fabien Gillet-Chaulet, Mondher Chekki, Gael Durand, Olivier Gagliardini, and Nicolas Jourdain
Wed, 26 Apr, 09:40–09:50  Room 1.61/62

Increasing the largest stable time-step size in ice flow models  
André Löfgren, Josefin Ahlkrona, Thomas Zwinger, Christian Helanow, and Denis Cohen
Wed, 26 Apr, 10:00–10:10  Room 1.61/62

- please contact us in case of additions or corrections should to be applied

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Hysteretic evolution of ice rises and ice rumples in response to variations in sea level

LowHysteresisIce rises and ice rumples are locally grounded features found in coastal Antarctica and are surrounded by otherwise freely floating ice shelves. In both cases, local highs in the bathymetry are in contact with the ice shelf from below, thereby regulating the large-scale ice flow, with implications for the upstream continental grounding line position. We investigate ice rises and ice rumples using a three-dimensional full Stokes ice flow model under idealised scenarios. The simulations span end-member basal friction scenarios of almost stagnant and fully sliding ice at the ice–bed interface. We analyse the interaction with the surrounding ice shelf by comparing the deviations between the non-local full Stokes surface velocities and the local shallow ice approximation (SIA). Deviations are generally high at the ice divides and small on the lee sides. On the stoss side, where ice rise and ice shelf have opposing flow directions, deviations can be significant. During sea level increase and decrease experiments, transitions from ice rise to ice rumple occur (and vice versa) and divide migration is more abrupt the higher the basal friction. We identify a hysteretic response of ice rises and ice rumples to changes in sea level, with grounded area being larger in a sea-level-increase scenario than in a sea-level-decrease scenario. This hysteresis shows not only irreversibility following an equal increase and subsequent decrease in sea level but also that the perturbation history is important in determining the current ice rise or ice rumple geometry.

Read more: Henry A. C. J., R. Drews, C. Schannwell and V. Višnjević, 2022. Hysteretic evolution of ice rises and ice rumples in response to variations in sea level, The Cryosphere, 16, 3889–3905, doi:10.5194/tc-16-3889-2022

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Threshold response to melt drives large-scale bed weakening in Greenland

maier2022Ice speeds in Greenland are largely set by basal motion, which is modulated by meltwater delivery to the ice base. Evidence suggests that increasing melt rates enhance the subglacial drainage network’s capacity to evacuate basal water, increasing bed friction and causing the ice to slow. This limits the potential of melt forcing to increase mass loss as temperatures increase. Here we show that melt forcing has a pronounced influence on dynamics, but factors besides melt rates primarily control its impact. Using a method to examine friction variability across the entirety of western Greenland, we show that the main impact of melt forcing is an abrupt north-to-south change in bed strength that cannot be explained by changes in melt production. The southern ablation zone is weakened by 20–40 per cent compared with regions with no melt, whereas in northern Greenland the ablation zone is strengthened. We show that the weakening is consistent with persistent basal water storage and that the threshold is linked to differences in sliding and hydropotential gradients, which exert primary control on the pressures within drainage pathways that dewater the bed. These characteristics are mainly set by whether a margin is land or marine terminating, suggesting that dynamic changes that increase mass loss are likely to occur in northern Greenland as temperatures increase. Our results point to physical representations of these findings that will improve simulated ice-sheet evolution at centennial scales.

Read more: Maier N., F. Gimbert and F. Gillet-Chaulet, 2022. Threshold response to melt drives large-scale bed weakening in Greenland, Nature 607, pages 714–720, doi:10.1038/s41586-022-04927-3

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