Elmer/Ice News


Elmer/Ice at EGU 2016

Written by Olivier Gagliardini on .


Don't miss the talks and posters making use of Elmer/Ice:

** Monday
* CR1.4/AS4.3 Glaciers and ice caps under climate change (co-organized)
Poster: 17:30–19:00 / Hall X4
- Martina Schäfer, Marco Möller, Thomas Zwinger, and John Moore. The influence of topographic feedback on a coupled mass balance and ice-flow model for Vestfonna ice-cap, Svalbard

** Tuesday
* CR5.1 Modelling ice sheets and glaciers
Poster: 17:30–19:00 / Hall X4
- Julien Brondex, Olivier Gagliardini, Fabien Gillet-Chaulet, and Gael Durand. Influence of damage and basal friction on the grounding line dynamics

- Josefin Ahlkrona, Per Lötstedt, and Thomas Zwinger. Dynamically coupling the full Stokes equations and the SIA - the ISCAL method

* CR5.2 Subglacial Environments of Ice Sheets and Glaciers
Poster 17:30–19:00 / Hall X4

- Dorothée Vallot, Rickard Pettersson, Doug Benn, Adrian Luckman, Olivier Gagliardini, Fabien Gillet-Chaulet, Thomas Zwinger, Jack Kohler, Ward van Pelt, and Björn Claremar. Seasonal subglacial state under Kronebreen, Svalbard - inversion and sliding laws.

* CR5.3/OS2.10 Ice shelves and tidewater glaciers - dynamics, interactions, observations, modelling (co-organized)
Oral: 13:30–17:00 / Room L2
- 15h30-15h45: Martin O'Leary, Bernd Kulessa, Adam Booth, Paul Holland, Daniela Jansen, Ed King, Adrian Luckman, Dan McGrath, and Thomas Zwinger. Inferring the viscous and elastic properties of a suture zone in Larsen C

** Friday
* CR 13 Reconstructing paleo ice dynamics: Comparing and combining field-based evidence and numerical modeling
Oral: 10:30–12:00 / Room L2
- 10h30-10h45: Denis Cohen, Fabien Gillet-Chaulet, Thomas Zwinger, Horst Machguth, Wilfried Haeberli, and Urs H. Fischer Basal conditions and flow dynamics of the Rhine glacier, Alps, at the Last Glacial Maximum.

Poster: 13:30–15:00 / Hall X4
- Guillaume Jouvet, Denis Cohen, Julien Seguinot, and Fabien Gillet-Chaulet. Inconsistent Last Glacial Maximum ice thickness of the Rhine glacier between geomorphological reconstructions and two numerical models.





Where shelf-ice turns passive

Written by Olivier Gagliardini on .


NCC JohannesThe decadal record of ice-shelf recession and break-up on the Antarctic Peninsula reveals that these vast slabs of floating ice restrain the sea-level relevant outflow from the upstream, well-grounded tributary glaciers. One of the key questions in projecting this outflow for the whole of Antarctica is how far ice-front recession may progress before important dynamic consequences are anticipated. This question is addressed in a recently published article in Nature Climate Change which relies on a continental-scale data assimilation with Elmer/Ice. Details of this assimilation were already presented in an accompanying article published earlier in The Cryosphere. The aim of the data assimilation was to quantify the buttressing effect on ice shelves relying on the inferred stress regime. If maximum buttressing showed values below a threshold, which itself was inferred from generic calving experiments, ice was considered dynamically passive. As long as the calving only removes this passive shelf-ice (PSI) portion, no important dynamic consequences are expected. The results show that 13 % of the total ice-shelf surface of Antarctica hold PSI with contrasting results across the continent. The presented analysis draws again the attention to the Amundsen and Bellingshausen sea sectors, where the PSI area fraction is notably lower, with regional averages of 7 and 5 %, respectively.

News written by Johannes J. Fürst.

Fürst, J. J., G. Durand, F. Gillet-Chaulet, L. Tavard, M. Rankl, M. Braun and O. Gagliardini, 2016. The safety band of Antarctic ice shelves, Nature Climate Change, doi:10.1038/NCLIMATE2912.




Impact of mesh resolution for MISMIP and MISMIP3d experiments

Written by Olivier Gagliardini on .

frictionThe dynamical contribution of marine ice sheets to sea level rise is largely controlled by grounding line (GL) dynamics. Two marine ice sheet model intercomparison exercises, namely MISMIP and MISMIP3d, have been proposed to the community to test and compare the ability of models to capture the GL dynamics. Both exercises are known to present a discontinuity of the friction at the GL, which is believed to increase the model sensitivity to mesh resolution. Here, using Elmer/Ice, the only Stokes model which completed both intercomparisons, the sensitivity to the mesh resolution is studied from an extended MISMIP experiment in which the friction continuously decreases over a transition distance and equals zero at the GL. Using this MISMIP-like setup, it is shown that the sensitivity to the mesh resolution is not improved for a vanishing friction at the GL. For the original MISMIP experiment, i.e. for a discontinuous friction at the GL, we further show that the results are moreover very sensitive to the way the friction is interpolated in the close vicinity of the GL. In the light of these new insights, and thanks to increased computing resources, new results for the MISMIP3d experiments obtained for higher resolutions than previously published are made available for future comparisons as the Supplement.

Gagliardini O., J. Brondex, F. Gillet-Chaulet, L. Tavard, V. Peyaud and G. Durand, 2016. Brief communication: Impact of mesh resolution for MISMIP and MISMIP3d experiments using Elmer/Ice, The Cryosphere, 10, 307-312, doi:10.5194/tc-10-307-2016.

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