COLLABORATIVE RESEARCH: Velocity Field, Force Budget, and Basal Conditions of a Soft-Bedded Glacier, Breidamerkurjokull, Iceland

这是华盛顿大学和加州圣克鲁斯大学的主要研究人员之间的合作建议。来自喷气推进实验室（JPL）的科学家将参与其中。其他参与者是来自冰岛大学和德国理工学院（ETH）的科学家。主要研究人员将通过测试以下假设来解决冰川尺度上软层冰运动的物理问题：冰岛瓦特纳冰盖上的布雷达默尔库冰盖的力平衡和运动速度是由下垫层控制的，而不是由其他因素如粘点、纵向拉伸/压缩、在持续的气候变化和海平面上升的背景下，需要了解控制冰运动的物理学来预测山地冰川和冰盖的未来行为。Breidamerkurjokull是一个冰川出水口，在发展冰川运动的新范式方面发挥了重要作用，在这种范式中，冰本身被动地在变形的土床上移动。这种创新的机制已经被用来解释一系列广泛的冰川学现象，如快速冰运动和冰川沉积物的高速率运输。我们对冰下土坯变形的了解大多来自于钻孔和实验室实验，在这些实验中，我们研究的是~0.1到~ 1米的短长度尺度。然而，为了改进软层冰川模型，需要了解在~100 ~ ~1000 m更长的空间尺度上控制冰流速率的物理因素。这个为期一年的项目将包括收集冰面速度和地形（空间分辨率为100米）和床地形（空间分辨率为几百米）的新数据。实地工作将包括利用破冰雷达和探地雷达以及全球定位系统进行调查。将利用合成孔径雷达干涉测量法从卫星图像生成额外数据。这些数据将分别应用力平衡和传递函数反演计算Breidamerkurjokull下基底剪应力和基底阻力的空间分布。这项研究将提高目前对冰-土相互作用及其对冰块流动的控制的理解，并可能有助于预测现代冰块是否会损害当地或全球的社会利益，例如，通过全球海平面的变化或山地冰川的涌动。

0136141TulaczykThis is a collaborative proposal between Principal Investigators at the Universities of Washington and California-Santa Cruz. Scientists from the Jet Propulsion Laboratory (JPL) will be involved. Other participants are scientists from the University of Iceland and Eidgenossische Technische Hochschule (ETH). The Principal Investigators will address the glacier-scale physics of soft-bedded ice motion by testing the hypothesis that the force balance and the rate of motion of Breidamerkurjokull on the Vatnajokull ice cap, Iceland is controlled by the underlying till bed and not by other factors such as sticky spots, longitudinal stretching/compression, marginal shear) Understanding the physics that govern ice motion is needed to make predictions on the future behavior of mountain glaciers and ice sheets in the context of the ongoing climate change and sea-level rise. Breidamerkurjokull, an outlet glacier draining, has played a significant role in developing a new paradigm of glacier motion, in which the ice itself rides passively on top of a deforming till bed. This innovative mechanism has been used to explain a wide array of glaciological phenomena such as fast ice motion and high rates of glacial sediment transport. Much of what is known about subglacial till deformation is derived from borehole and laboratory experiments where the process is studied at short length scales of ~0.1 to ~ 1 meters (m). However, to improve models of soft-bedded glaciers, an understanding of the physical factors controlling the ice-flow rate over much longer spatial scales of ~100 to ~1000 m is required This one-yearproject will involve collection of new data on ice surface velocity and topography (spatial resolution of 100 m) and bed topography (spatial resolution of several hundred meters). The fieldwork will include surveys with ice-penetrating and ground penetrating radar and Global Positioning System. Additional data will be generated from satellite imagery using Synthetic Aperture Radar Interferometry. The data will be used to calculate the spatial distribution of basal shear stress and basal resistance beneath Breidamerkurjokull employing the force-balance and transfer-function inversions, respectively. This research should improve the current understanding of ice-till interactions and of their control over flow of ice masses and may help predict whether modern ice masses will harm local or global societal interests through, for instance, changes in the global sea level or surges of mountain glaciers.