006-esco2020.txt (2324B)
1 [1]ESCO 2020, the 7th European Seminar on Computing, was held between June 8 2 and 12. I presented my current research on ice-sheet and sediment mechanics. 3 4 Full abstract: 5 6 Title: The role of granular mechanics and porous flow for ice 7 sheet behavior in a changing climate 8 9 Ice sheets and glaciers commonly flow over sedimentary deposits, in 10 particular in areas of fast ice flow. The basal sediments are weakened by 11 high water pressure provided by ice melt and limited drainage. Areas of 12 fast flow are primary contributors to sea-level rise, so an accurate 13 understanding of the thermomechanical multiphysics problem of ice, water, 14 and sediment is crucial for predicting dynamical behavior under future 15 climate scenarios. The in-situ observational basis from borehole 16 measurements shows that the subglacial environment is highly dynamic. Water 17 pressures, strain rate, and glacial sliding patterns are extremely variable 18 in time and space, and hint towards significant complexity beyond current 19 modelling approaches. Sediment transport by ice flow reshapes the bed, and 20 can feed back to the ice flow physics. In this presentation I explain our 21 efforts to numerically describe the subglacial sediment mechanics and fluid 22 dynamics, and how the processes affect ice sheet behavior. GPU-based 23 particle-scale simulations using the discrete element method and porous 24 fluid dynamics provide detailed insight into sediment and meltwater 25 dynamics. However, the intense computational requirements severely limit 26 their applicability to coupled simulations of ice and bed. Our newest 27 efforts use continuum models of non-local granular fluidity to simulate 28 essential behavior on larger spatial and temporal scales. We show that the 29 variability observed in field borehole measurements can be explained by 30 considering the coupled dynamics of the ice-water-sediment system. From 31 these dynamics ice flow has the ability to rapidly reshape its bed, 32 providing additional feedbacks to ice contribution to sea level in a 33 changing climate. 34 35 Slides and video below: 36 37 - slides: https://adamsgaard.dk/npub/esco2020-damsgaard.pdf 38 - video: https://adamsgaard.dk/video/damsgaard_esco2020.mp4 39 40 41 References: 42 43 [1] https://www.esco2020.femhub.com/