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
Mon, 24 Apr, 08:35–08:45 Room 0.16
Numerical modelling of rapidly-rising glacier outburst floods
Mon, 24 Apr, 11:45–11:55 Room L3
Seasonal and inter annual effects of meltwater runoff on ice dynamics in Northeast Greenland
Mon, 24 Apr, 14:00–15:45 Hall X5 | X5.237
A periodic visco-elastic model for crevasses propagation in marine ice shelves
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
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
Tue, 25 Apr, 11:15–11:25 Room L3
Constraining the overall future projection of Upernavik Isstrøm by observations
Tue, 25 Apr, 12:05–12:15 Room L3
Modelling the kinematic evolution of valley-scale folding in surge-type glaciers using Elmer/Ice
Tue, 25 Apr, 16:15–16:25 Room L2
Large-amplitude perturbation experiments to assess the unstable behaviour of AIS in the near future
Tue, 25 Apr, 17:25–17:35 Room L2
On the effect of damage on the recent changes in the Amundsen Sea Sector
Tue, 25 Apr, 17:45–17:55 Room L2
Modelling the three-dimensional stratigraphy of an ice rise
Wed, 26 Apr, 09:20–09:30 Room 1.61/62
Elmer/Ice results on the CalvingMIPintercomparison project using a level-set function
Wed, 26 Apr, 09:40–09:50 Room 1.61/62
Increasing the largest stable time-step size in ice flow models
Wed, 26 Apr, 10:00–10:10 Room 1.61/62
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Ice 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.
Ice 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.
