Observational constraints on glacier sliding laws

冰川是世界上许多地方重要的季节性淡水来源，包括加拿大西部。格陵兰岛和南极洲等大陆规模的冰盖在调节全球海平面方面发挥着重要作用。这两种类型的冰块通过降雪和融化对周围气候都很敏感，它们对气候变化的反应主要取决于其中的冰如何流动。冰在基岩或沉积物上的滑动通常是冰川或冰盖整体流动的主要组成部分，滑动速度会根据润滑融水的输入而发生显着变化。因此，冰川和冰盖动力学的计算机模拟需要精确的滑动表示。然而，由于大多数冰川床的不可接近性，冰川滑动的直接研究受到限制，许多模拟依赖于纯粹的滑动理论模型。拟议的研究旨在为滑动模型提供更好的观测约束。具体而言，我将利用全球定位系统和卫星雷达技术测量育空地区冰川滑动速度的时空变化。使用一种称为逆模型的数学工具，将根据这些测量结果计算河床处的摩擦力，并将其与通过现场仪器获得的冰川底部水压的直接测量结果相关联。研究的目的是建立冰川床摩擦力、滑动速度和润滑基底水压力之间的定量联系。

Glaciers are an important seasonal source of freshwater in many places around the world, including the Canadian West. Continental-scale ice sheets such as those in Greenland and Antarctica play an important role in regulating global sea levels. Both types of ice masses are sensitive to their ambient climate through snowfall and melting, and their response to a change in climate depends crucially on how the ice in them flows. Sliding of ice over bedrock or sediments is often a major component in the overall flow of a glacier or ice sheet, and sliding speeds can vary dramatically according to the input of lubricating meltwater to the bed. Computer simulations of glacier and ice sheet dynamics therefore require an accurate representation of sliding. However, due to the inaccessibility of most glacier beds, direct studies of glacier sliding have been limited and many simulations rely on purely theoretical models of sliding. The proposed research aims to provide better observational constraints on models of sliding. Specifically, I will use Global Positioning System and satellite-based radar technology to measure spatial and temporal variations in the sliding speed of a glacier in the Yukon Territory. Using a mathematical tool known as an inverse model, friction at the bed will be calculated from these measurements, and will be correlated to direct measurements of water pressure at the base of the glacier obtained through in-situ instrumentation. The aim of the research is to establish quantitative links between friction at the glacier bed, sliding velocity and the pressure of lubricating basal water.