Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations

• Published in: Journal of Glaciology
• Main Authors: Benn, DI, Astrom, J, Zwinger, T, Todd, J, Nick, FM, Cook, S, Hulton, NRJ, Luckman, A
• Format: Article in Journal/Newspaper
• Language: English
• Published: Int Glaciol Soc 2017
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Ice Sheet; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2017.41; http://ecite.utas.edu.au/119229

The simple calving laws currently used in ice-sheet models do not adequately reflect the complexity and diversity of calving processes. To be effective, calving laws must be grounded in a sound understanding of how calving actually works. Here, we develop a new strategy for formulating calving laws, using (a) the Helsinki Discrete Element Model (HiDEM) to explicitly model fracture and calving processes, and (b) the continuum model Elmer/Ice to identify critical stress states associated with HiDEM calving events. A range of observed calving processes emerges spontaneously from HiDEM in response to variations in ice-front buoyancy and the size of subaqueous undercuts. Calving driven by buoyancy and melt under-cutting is under-predicted by existing calving laws, but we show that the location and magnitude of HiDEM calving events can be predicted in Elmer/Ice from characteristic stress patterns. Our results open the way to developing calving laws that properly reflect the diversity of calving processes, and provide a framework for a unified theory of the calving process continuum.