Life Sciences Faculties

Ice sheets can dramatically impact the state of climate. This is due to their capacity to modify the planetary energy balance through variations in the ice cover and mass. A major question is how rapidly could such modification occur and to what extent ? This question can be addressed by investigating phenomena that involve relatively large mass flux of ice into the ocean, such as ice calving and rifting, ice streams, and melting. Many of these processes involve interactions between the ice sheet and the underlying bedrock or ocean. We model ice sheets as buoyancy-driven flows of nonlinear (non Newtonian) fluid and explore the resulted flow dynamics and stability due to different friction conditions along the base of the ice. I will show results from scaled laboratory experiments and theoretical modelling of several flows under different friction conditions that evolve patterns reminiscent to those that emerge in glacier ice flows. Specifically, the basal friction that we consider ranges from no-slip conditions, in which radially symmetric flows are stable, to free-slip conditions, in which such flows are unstable, developing patterns reminiscent to ice rifts and ice bergs. Under mixed conditions of friction, an initially radially symmetric flow can be either stable, or develop patterns reminiscent to ice streams. Our insights may have implications to predicting ice flow on Earth and possibly on other planetary objects.