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.冰流通量由重力、基底摩擦力与侧向拖曳力之间的平衡所调控。在冰流与相邻低速冰脊之间的剪切边界（shear margin）中，会产生显著的粘性生热。至关重要的是，随温度变化的粘度分布将侧向拖曳力与边际应变率关联起来，而边际应变率的积分结果直接决定冰流的流速。温冰川区（Temperate zones）可形成并支持更快的冰流，但冰脊会输送冷冰，引发平流冷却，从而抑制这一流动趋势。在Hunter及其同事2021年发表于《冰川学期刊》（Journal of Glaciology）的论文《冰流剪切边界的热调控机制》中，我们提出了一个二维（含三个速度分量）的稳态模型，用于探究冰流剪切边界的热调控机制，并在理想化截面中识别出温冰川条件形成的关键尺度律。本数据集包含我们在该研究中使用商用有限元软件COMSOL生成的数值数据，这些数据通过Matlab的m脚本文件（m-files）绘制成该论文中的图3、4、7和8。本数据集为参数扫描模拟的输出结果：我们选取了覆盖南极冰流已观测或推断得到的各类工况的控制参数，通过改变这些参数以探究冰流行为的变化规律。