Collaborative Research: Water Storage and Routing Within Glaciers via Planar Voids, a New Model of Glacier Hydrology

随着气候变暖，融水水文及其对冰川运动的影响将成为大冰块热力和动力过程的一个日益重要的方面。冰盖的滑动稳定性对海平面、海洋环流和一般气候系统都有影响，对全球重要过程有重大影响，因此值得充分了解。不幸的是，在厚厚的冰盖上，对水输入和增强运动之间的机械联系进行实地调查是困难的。这个问题激发了人们对较小的山地冰川的水文和动力学的兴趣，在那里可以利用可控的规模来研究关键的冰川过程。如果我们不进一步了解冰川内部和下方的水文过程，我们就不能指望完全了解冰川的运动。了解这些过程将极大地帮助我们解释冰川运动的时间/空间变动性，并最终帮助我们预测冰川未来的变化或重建给定冰川情景下的气候历史。考虑到这些目标，首席研究人员将专注于提高我们对水文过程和基础滑动之间关键联系的认识：冰川水储存和地表水到床的路径机制。最近在Bench冰川和多热储冰川的研究揭示了一个由平面空隙空间组成的冰川网络。因为它们是非常不同的冰川，所以空隙很可能是无处不在的冰川特征。两个小组都观察到水流经空隙。英格兰水流通过裂缝网络是一个水文模型，与目前公认的半圆形管道（Rthlisberger管道）的乔木网络模型形成鲜明对比。首席研究人员将验证这一假设：平面空洞是冰川水文系统的重要组成部分，能够将水从地表储存和输送到河床，或许还能沿着河床输送。这项工作将对他们模拟和预测水从冰川表面流向冰川床的能力产生重大影响。这项工作将在阿拉斯加的Bench冰川进行，那里有一个已知的冰川空洞网络。他们将通过一系列钻孔实验和地球物理成像技术来验证他们的假设。许多地球物理实验将利用以前未曾应用于冰川的数据采集和处理方法。因此，这项工作将促进我们对冰川学过程和浅层地球物理成像的理解。

As the climate warms, meltwater hydrology and water's influence on glacier motion will be an increasingly important aspect of thermal and dynamic processes of large ice masses. With influence on sea level, ocean circulation, and the general climate system, the sliding stability of ice sheets has strong bearing on globally important processes and, thus, warrants full understanding. Unfortunately, in situ investigations of the mechanical linkages between water input and enhanced motion are difficult on thick ice sheets. This problem motivates interest in the hydrology and dynamics of smaller mountain glaciers, where the manageable scale can be utilized to investigate key glaciological processes. We cannot expect to ever fully understand basal motion without advancing our knowledge of the hydrological processes in operation within and beneath glaciers. Understanding of these processes will greatly aid our ability to interpret time/space variability in glacier motion, and ultimately, our ability to predict future changes to glaciers or reconstruct climate history under given glacial scenarios. With these goals in mind, the Principal Investigators will focus on advancing our knowledge of a critical link between hydrological processes and basal sliding: mechanisms of englacial water storage and routing of surface water to the bed. Recent work at Bench Glacier and work at the polythermal Storglaciren have revealed an englacial network of planar void spaces. Because these are very different glaciers, it is probable that void spaces are a ubiquitous englacial feature. Water has been observed flowing through the voids by both groups. Englacial water flow through a fracture network is a hydrological model in stark contrast to the currently accepted model of an arborescent network of semi-circular conduits (Rthlisberger conduits). The Principal Investigators will test the hypothesis: planar voids are an important part of the englacial hydrological system, capable of storing and routing water from the surface to the bed and perhaps, along the bed. This work will have strong implications for their ability to model and predict the routing of water from a glacier surface to its bed. This work will be conducted at Bench Glacier, Alaska, where there is a known englacial void network. They will test their hypothesis using a series of borehole experiments and geophysical imaging techniques. Many of the geophysical experiments will utilize data acquisition and processing methodologies that have not previously been applied to glaciers. Hence, this work will advance our understanding of both glaciological processes and shallow geophysical imaging.