Department Seminar: Meghana Ranganathan

Title: The coupling between fracture and flow in ice sheets

Abstract: Mass loss from the Antarctic Ice Sheet occurs due to the flow of ice, which transports ice from the interior of ice sheets towards the ocean, and the fracture of ice, which ultimately is responsible for calving events in which large chunks of ice separate from the ice sheet to form icebergs. Understanding and modeling the processes of ice flow and fracture, therefore, is critical to accurately represent ice sheet dynamics in models that project future sea-level rise. While flow and fracture are typically treated as separate processes, in reality they are coupled: accelerating ice flow and deformation preconditions regions of ice sheets for fracture, and those fractured zones weaken the structural integrity of the glacier, enabling more rapid flow. This coupling may have significant implications for the stability of Antarctic glaciers. In this talk, I will investigate the nature of this two-way coupling between ice flow and fracture. We find that incorporating fracture effects on ice flow can result in a ~30% enhancement to the ice mass loss that occurs from changes to climate forcing, but that this effect is significantly impacted by the microstructural nature of fracture processes. Ultimately, this work seeks to highlight the importance of microphysics on ice sheet dynamics.