Collaborative Research: Freeze-on of Subglacial Sediments in Experiments and Theory

南极和格陵兰冰盖变化最快的地区对海平面上升的贡献最大，它们被促进冰川运动的软沉积物所覆盖。冰川冰可以渗透到这些沉积物中几米，这取决于冰川底部的温度和水压。为了了解冰川下沉积物中的冰渗透如何影响冰川滑动，该团队将在相关温度和压力条件下进行实验室实验，并将结果与最先进的数学模型进行比较。通过威斯康星大学麦迪逊分校、达特茅斯学院和梅诺明民族学院之间的本科生研究交流，美洲原住民学生将在一个夏天进行实验室实验，并在下一个夏天进行数学理论。冰-沉积物相互作用是冰盖和地形发育模型的核心组成部分。有限的过程理解给用于预测海平面上升的冰盖模型带来了关键的不确定性。这种不确定性突显了开发经过实验验证的、理论上可靠的对冰-沉积物界面过程的描述的重要性。为了实现这一目标，该团队的目标是建立在长期建立的理论、实验和现场调查的基础上，这些调查已经阐明了预融和表面能效应在控制土壤中冻胀动态方面的核心作用。项目成员将从理论上描述并通过实验测试冰-沉积物底部界面预融的作用。这些实验旨在提供定量的洞察力，以了解冰渗透到沉积物中对冰川滑动、侵蚀和冰下地貌演变的影响。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The fastest-changing regions of the Antarctic and Greenland Ice Sheets that contribute most to sea-level rise are underlain by soft sediments that facilitate glacier motion. Glacier ice can infiltrate several meters into these sediments, depending on the temperature and water pressure at the base of the glacier. To understand how ice infiltration into subglacial sediments affects glacier slip, the team will conduct laboratory experiments under relevant temperature and pressure conditions and compare the results to state-of-the-art mathematical models. Through an undergraduate research exchange between University of Wisconsin-Madison, Dartmouth College, and the College of Menominee Nation, Native American students will work on laboratory experiments in one summer and mathematical theory in the following summer.Ice-sediment interactions are a central component of ice-sheet and landform-development models. Limited process understanding poses a key uncertainty for ice-sheet models that are used to forecast sea-level rise. This uncertainty underscores the importance of developing experimentally validated, theoretically robust descriptions of processes at the ice-sediment interface. To achieve this, the team aims to build on long-established theoretical, experimental, and field investigations that have elucidated the central role of premelting and surface-energy effects in controlling the dynamics of frost heave in soils. Project members will theoretically describe and experimentally test the role of premelting at the basal ice-sediment interface. The experiments are designed to provide quantitative insight into the impact of ice infiltration into sediments on glacier sliding, erosion, and subglacial landform evolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.