Thermal Controls on Ice Stream Shear Margins, Antarctica, December 2020

Ice stream discharge responds to a balance between gravity, basal friction, and lateral drag. Appreciable viscous heating occurs in shear margins between ice streams and adjacent slow-moving ice ridges. Crucially, the temperature-dependent viscosity distribution connects lateral drag to marginal strain-rates that integrate to determine ice stream velocity. Temperate zones can develop and accommodate much faster flow, however, ice ridges supply cold ice that drives advective cooling, and reduces this tendancy. In Hunter and coworkers, "Thermal Controls on Ice Stream Shear Margins", J. Glaciology, 2021, we present a two-dimensional (three velocity component), steady-state model designed to explore the thermal controls on ice stream shear margins, and identify key scalings for the emergence of temperate conditions within an idealized cross-section. Here, we include the data that we generated using the commercial finite element software, COMSOL, and displayed using m-files in Matlab in Figures 3, 4, 7 and 8 from that publication. This represents the output of parameter sweeps that examine changes in behavior with changing control parameters chosen to span a range of conditions that are observed or inferred for Antarctic ice streams.