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

合作研究：冰川流动和景观演化模型滑动定律的发展

基本信息

批准号：
1660972
负责人：
Neal Iverson
金额：
$ 35.2万
依托单位：
Iowa State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2020-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1660972&HistoricalAwards=false
关键词：
Collaborative research Development sliding laws

项目摘要

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.

通过该项目，开发了预测冰川和冰盖滑动速度所需的数学关系（即滑动定律）。现有滑动规律形式的可变性给冰川流动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规律，并将冰川内和冰川下碎片的摩擦阻力纳入其中，从而改进了滑动规律。因此，这项研究有可能提高预测的冰川流模型和评估其不确定性。现场和实验室测量相结合的三维流动建模，完全包围的滑动行为的范围可能的目标。对加拿大和瑞士因冰川消退而暴露的冰川床地形进行了高分辨率测量和统计描述。此外，在实验室实验中测量滑动的摩擦阻力，其中含有碎片的冰在岩床上滑动。这两组测量结果用于冰川滑动的数值模拟，产生滑动速度，应力在床，床地形，冰中的碎片浓度之间的关系，以及水饱和沉积物从岩石中分离冰的面积范围。