In this latest article on ISMIP6-Antarctica intercomparison (including contribution from Elmer/Ice),  a closer look is taken on the results for high carbon emission scenarios. The work focuses on key glaciers around the Antarctic Ice Sheet in order to quantify their projected dynamic mass loss through increased ice discharge into the ocean in response to changing oceanic conditions. Particular attention is given to glaciers contributing the most to sea level rise, as well as their vulnerability to changes in oceanic conditions.  These key glaciers - alongside the whole ice-sheet - in the further are investigated for the different sources of uncertainty and their relative role in projections. The findings are that in addition to the "usual suspects" in W-Antarctic ice-sheet (that be Thwaites and Pine Island) also outlet systems in E-Antarctica (Moscow University and Totten) show high sensitivity to increased oceanic ice-melt. Further, the uncertainties of the choice of climate models and the parametrization of the ocean melt have been investigated. Yet, overall, the highest uncertainty in dynamic ice-loss seems to be coming from the choice of the ice-sheet model. 

Read more:

Seroussi, H., Verjans, V., Nowicki, S., Payne, A. J., Goelzer, H., Lipscomb, W. H., Abe-Ouchi, A., Agosta, C., Albrecht, T., Asay-Davis, X., Barthel, A., Calov, R., Cullather, R., Dumas, C., Galton-Fenzi, B. K., Gladstone, R., Golledge, N. R., Gregory, J. M., Greve, R., Hattermann, T., Hoffman, M. J., Humbert, A., Huybrechts, P., Jourdain, N. C., Kleiner, T., Larour, E., Leguy, G. R., Lowry, D. P., Little, C. M., Morlighem, M., Pattyn, F., Pelle, T., Price, S. F., Quiquet, A., Reese, R., Schlegel, N.-J., Shepherd, A., Simon, E., Smith, R. S., Straneo, F., Sun, S., Trusel, L. D., Van Breedam, J., Van Katwyk, P., van de Wal, R. S. W., Winkelmann, R., Zhao, C., Zhang, T., and Zwinger, T., 2023. Insights into the vulnerability of Antarctic glaciers from the ISMIP6 ice sheet model ensemble and associated uncertainty. The Cryosphere 17. doi:10.5194/tc-17-5197-2023

Choosing the location Sermeq Kujalleq (Store Glacier), the calving behaviour of a typical Greenlandic tidewater glacier  was investigated using the crevasse-depth (CD) calving law in Elmer/Ice and compared to results with the discrete element model HiDEM as well as observational data. This particular glacier has a stable front position due to a compressive arch between lateral pinning points,  which regularly lets ice that advances seawards across this arch calve back, whereas any undercut land inwards is countered by a readvance to the stable front position, which acts as an attractor between unstable super-critical and sub-critical regimes. It turns out that such a self-organising critical system can be very well described with a CD calving law in combination with a position (rather than a rate-based) calving algorithm in a continuum ice-flow model (Elmer/Ice) that resolves the major stress components at the ice front.

Read more:

Benn, D.I., J. Todd, A. Luckman, S. Bevan, T.R. Chudley, J. Åström, T. Zwinger, S. Cook, P. Christoffersen, 2023. Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law. Journal of Glaciology 1-17. doi:10.5194/10.1017/jog.2023.81

The first online Elmer/Ice beginner's course was taking place from November 23 to 27, with a self-study preparation week based on instruction videos from 16. to 20. November. In total there were about 40 people from all over the world enrolled in this course, which was free of charge and supported by IGE, Grenoble and CSC in Espoo. The wide spread of timezones of the participants implied that every Zoom online session from the morning was repeated in the evening. The material (slides, videos and input files) is  still accessible via the course pageand of course can be further used as reference or self-study material.

Besides some constructive suggestions on how to improve this course format, the feedback to the course was generally positive. A few quotes from the feedback form:

Thank you for the efforts and for a very well designed introduction course!

Thank you, you guys are the best!

I would like to thank you for the entire Elmer/Ice team for providing this great opportunity to learn the model. This was my first time with Elmer/Ice and I have found the model very important and useful in my research work. The course was detailed, informative and well structured. The training session was interactive and encouraged me to use the model in my research work. I am motivated to use the model in my current and future research.

Thank you very much for taking the time to run this course. It was fantastic to get an introduction to Elmer and to realise the possibilities it presents. I look forward to beginning to use Elmer in the near future.

 Encouraged by these positive reactions, the Elmer/Ice team is considering to provide courses of the same online format also in the post-pandemic future.

This study presents results from ice flow model simulations from 13 international groups focusing on the evolution of the Antarctic ice sheet during the period 2015–2100 as part of the Ice Sheet Model Intercomparison for CMIP6 (ISMIP6). Elmer/Ice is one of these models, which are forced with outputs from a subset of models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), representative of the spread in climate model results. Simulations of the Antarctic ice sheet contribution to sea level rise in response to increased warming during this period varies between −7.8 and 30.0 cm of sea level equivalent (SLE) under Representative Concentration Pathway (RCP) 8.5 scenario forcing. These numbers are relative to a control experiment with constant climate conditions and should therefore be added to the mass loss contribution under climate conditions similar to present-day conditions over the same period. The simulated evolution of the West Antarctic ice sheet varies widely among models, with an overall mass loss, up to 18.0 cm SLE, in response to changes in oceanic conditions. East Antarctica mass change varies between −6.1 and 8.3 cm SLE in the simulations, with a significant increase in surface mass balance outweighing the increased ice discharge under most RCP 8.5 scenario forcings. The inclusion of ice shelf collapse, here assumed to be caused by large amounts of liquid water ponding at the surface of ice shelves, yields an additional simulated mass loss of 28 mm compared to simulations without ice shelf collapse. The largest sources of uncertainty come from the climate forcing, the ocean-induced melt rates, the calibration of these melt rates based on oceanic conditions taken outside of ice shelf cavities and the ice sheet dynamic response to these oceanic changes. Results under RCP 2.6 scenario based on two CMIP5 climate models show an additional mass loss of 0 and 3 cm of SLE on average compared to simulations done under present-day conditions for the two CMIP5 forcings used and display limited mass gain in East Antarctica.

Seroussi, H., et al. , 2020. ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century, The Cryosphere, 14, 3033–3070, doi:10.5194/tc-14-3033-2020