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。大陆规模的冰盖，如格陵兰和南极洲的冰盖，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的气候很敏感，它们对气候变化的反应关键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，滑动速度可能会根据输入到床上的润滑融水的不同而显著不同。因此，冰川和冰盖动态的计算机模拟需要准确的滑动表示。然而，由于大多数冰川床无法进入，对冰川滑动的直接研究一直受到限制，许多模拟依赖于纯粹的理论滑动模型。提出的研究旨在为滑动模型提供更好的观测约束。具体地说，我将使用全球定位系统和基于卫星的雷达技术来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出床面的摩擦力，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。这项研究的目的是建立冰床摩擦力、滑动速度和润滑基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.