Collaborative research: Development of sliding laws for glacier-flow and landscape-evolution models

通过这个项目，预测冰川和冰盖滑动速度所需的数学关系（即滑动规律）得到了发展。现有滑动规律形式的可变性给冰川流动的计算机模型的结果增加了很大的不确定性。这些计算机模型是用来评估下个世纪冰川流失和由此导致的海平面上升以及研究冰川对岩石的侵蚀的主要工具。这项工作通过从冰川床的实际地形中推导出滑动定律，并将冰川内部和下方碎屑的摩擦阻力纳入其中，从而改进了滑动定律。因此，这项研究有可能改善对冰川流动模型的预测和对其不确定性的评估。现场和实验室测量与3D流动建模相结合，目标是完全覆盖滑动行为的范围。在加拿大和瑞士，冰川消退露出的冰川床地形以高分辨率测量，并进行统计描述。此外，在实验室实验中，包含碎片的冰在岩床上滑动，测量了滑动的摩擦阻力。这两组测量结果用于冰川滑动的数值模拟，得出滑动速度、河床应力、河床地形、冰中的碎屑浓度以及将冰与岩石分开的水饱和沉积物的面积范围之间的关系。

With this project, mathematical relationships needed to predict the sliding speeds of glaciers and ice sheets (that is, sliding laws) are developed. Variability of the forms of existing sliding laws adds major uncertainty to the results of computer models of glacier flow. These computer models are the principal tools used to both assess glacier wastage and resultant sea-level rise over the next century and to study rock erosion by glaciers. This work improves sliding laws by deriving them from the actual topography of glacier beds and incorporating the frictional resistance of debris within and underneath glaciers. Thus, this study has the potential to improve predictions of glacier-flow models and assessments of their uncertainty.Field and laboratory measurements are combined with 3D flow modeling, with the goal of fully bracketing the range of sliding behavior possible. The topography of glacier beds exposed by receding glaciers in Canada and Switzerland is measured at high resolution and statistically described. Also, frictional resistance to slip is measured in laboratory experiments in which ice containing debris is slid over a rock bed. These two sets of measurements are used in numerical simulations of glacier sliding that yield relationships among sliding speed, stresses at the bed, bed topography, debris concentration in ice, and areal extent of water-saturated sediment dividing ice from rock.