The search for ice as old as 1.5Myr requires the identification of places that maximize our chances to retrieve old, well-resolved, undisturbed and datable ice. One of these locations is very likely southwest of the Dome C summit, where elevated bedrock makes the ice thin enough to limit basal melting. A 3-D ice flow simulation is used to calculate five selection criteria, which together delineate the areas with the most appropriate glaciological properties. These selected areas (a few square kilometers) lie on the flanks of a bedrock high, where a balance is found between risks of basal melting, stratigraphic disturbances and sufficient age resolution. Within these areas, several sites of potential 1.5Myr old ice are proposed, situated on local bedrock summits or ridges. The trajectories of the ice particles towards these locations are short, and the ice flows over a smoothly undulating bedrock. These sites will help to choose where new high-resolution ground radar surveys should be conducted in upcoming field seasons.
Read more: Passalacqua O., M. Cavitte, O. Gagliardini, F. Gillet-Chaulet, F. Parrenin, C. Ritz and D. Young, 2018. Brief communication: Candidate sites of 1.5 Myr old ice 37 km southwest of the Dome C summit, East Antarctica, The Cryosphere, 12, 2167-2174, doi:10.5194/tc-12-2167-2018
Before the Nordic Branch IGS meeting this year in Rovaniemi, Finland, an Elmer/Ice beginners course will be held on October 22. And 23., 2018, at the Arcticum House in Rovaniemi. The course description and a registration link can be found from CSC’s training pages.
We are currently also planning for an advanced Elmer/Ice workshop taking place at the premises of CSC after the Nordic Branch meeting from October 29.-31., 2018. The registration page can also be found from CSC’s training pages. We will decide on October 7., if there is a sufficient amount of participants to have this course.
The built-in inversion capabilities of Elmer/Ice have been used to determine the change of basal friction coefficients below the glacier at Basin 3, Austfonna, during the acceleration phase of its recent surge. This time series, showing the unplugging of the stagnant ice front, was made possible by a highly temporal and spatial resolved set of satellite observations.
Observations also provided information on the crevasse field at the glacier, which was used to compare with the results obtained by the discrete element model, HiDEM, which was used to determine the instantaneous fractures as a reaction to the changing inverted basal friction. Identifying those crevasses that are deep enough to act as a path for surface water towards the bed and using a simplified hydraulic model, the possible mechanisms that lead to the surge of Basin 3 in early 2013 are discussed in this paper.
The picture shows the basal sliding velocities computed by Elmer/Ice as well as the flow path according to the hydraulic potential of water entering the deepest crevasses (red dots) that have been computed with HiDEM.
Read more: Gong, Y., Zwinger, T., Åström, J., Altena, B., Schellenberger, T., Gladstone, R., and Moore, J. C., 2018. Simulating the roles of crevasse routing of surface water and basal friction on the surge evolution of Basin 3, Austfonna ice cap. The Cryosphere, 12, 1563-1577, doi:10.5194/tc-12-1563-2018