The response of Antarctic ice streams to tidal forcing

冰从南极洲内部向海洋的运输主要受流经几个快速流动的冰流的流量的影响，这些冰流的行为很大程度上受其底部和冰-海洋界面上的固定点的条件的影响。冰速对不断变化的基本条件的响应是预测气候变化中未来行为的一个关键挑战。最近的观测表明，冰流的运动对海洋潮汐非常敏感，超过10公里(Gudmundsson 2006，Minchew等人)。2017年)表明冰川流动、侧缘剪切加热和冰下沉积物的孔压变化之间存在耦合。该项目旨在通过使用高分辨率的冰川运动在空间和时间上的测量来了解粘性冰与冰川下冰层随压力变化的流变性，以响应潮汐强迫。该项目结合了对南极一些关键地点的冰流运动响应潮汐强迫的可变性的卫星和GPS观测的分析，以及冰川在多孔弹性冰川下冰层上运动的简化模型(Hewitt等人，正在出版中)。这种简单的物理模型和最先进的观测相结合，结合了两个快速发展的科学领域--孔洞力学和遥感，以解决冰盖演化中与饱和流体的冰下沉积物的力学有关的基本问题。

The transport of ice from the interior of Antarctica to the oceans is dominated by the flux through several fast-flowing ice streams whose behaviour is greatly influenced by the conditions at their base and at grounding points along the ice-ocean interface. The response of the ice velocity to changing basal conditions presents a key challenge for predicting future behaviour in a changing climate. Recent observations have shown that the motion of ice streams is sensitive, over 10s of kilometres, to ocean tides (Gudmundsson 2006, Minchew et al. 2017) suggesting a coupling between the flow of glacial ice, shear heating at lateral margins, and pore pressure changes in subglacial sediment. This project aims to understand the nonlinear coupling of viscous ice with the pressure-dependent rheology of the subglacial till through the use of highly resolved measurements of glacial motion, both spatially and temporally, in response to the tidal forcing.This project combines analysis of satellite and GPS observations of the variability of ice stream motion in response to tidal forcing at a number of key Antarctic sites, along with simplified models of the motion of glacial ice over a poro-elastic subglacial till (Hewitt et al, in press). This combination of simple physical models and state-of-the-art observations combines two rapidly evolving scientific fields, poromechanics and remote sensing, to address fundamental questions in ice sheet evolution related to the mechanics of fluid-saturated subglacial sediments.