Collaborative Research: The Influence of Hydrofracture and Surface Melt Variability on Greenland Ice Sheet Flow

在格陵兰岛，与湖泊排水相关的水力压裂事件创造了从地面到床的管道，通过这些管道，表面融化物到达床的速度从夏季的融化流排放到突然的湖泊排水期间的大而短暂的脉冲。虽然最近的工作表明，增强的季节性润滑对格陵兰冰盖造成的不稳定影响可能比人们曾经担心的要小，但表面融化和冰流之间的相互作用仍然缺乏约束，其影响在目前的冰盖模型中没有得到很好的体现。该项目旨在通过对冰盖水力破裂的坚实的、基于物理的理解，以及在季节和年际时间尺度上表征地表融化对冰盖流动的影响，为改善未来的海平面上升评估做出贡献。获得这方面的知识是在模式推导的海平面预估中综合地表融化增加的影响的重要一步。研究人员将使用综合地面和卫星观测与数值模型相结合的实验设计来确定控制水力压裂的过程，并利用这种理解来确定格陵兰冰盖的面积是否会改变？在气候变暖的情况下，暴露在地表融水中的冰层将大幅增加。这项研究的结果将通过这些调查人员广泛的持续努力，包括K-12活动和公开讲座，向公众传播。一个摄影和写作团队的直接参与也将从当地的角度来理解和交流气候变化对格陵兰社区的影响。我们的结果也将直接引起科学家们的兴趣，他们正在努力了解格陵兰冰盖过去和未来的变化，包括理论和模型研究。该项目还将包括研究生直接参与WHOI和华盛顿大学的实地和研究活动。

Hydrofracture events associated with lake drainages in Greenland create surface-to-bed conduits through which surface melt reaches the bed at rates ranging from that of summer-long melt-stream discharge to that of large, transient pulses during sudden lake drainages. While recent work suggests that enhanced seasonal lubrication may have less of a destabilizing effect on the Greenland Ice Sheet than once feared, the interaction between surface melt and ice flow remains poorly constrained and its influence is not well represented in current ice-sheet models. This project aims to contribute toward improving future sea-level rise assessments by achieving a firm, physically based understanding of ice-sheet hydrofracture, and by characterizing the influence of surface melt on ice-sheet flow over seasonal and inter-annual time scales. Acquisition of this knowledge is an important step toward integrating the influence of increased surface melt in model-derived sea level projections. The investigators will use an experimental design of integrated ground- and satellite-based observations coupled to numerical models to determine the processes that govern hydrofracturing and use this understanding to determine whether the area of the Greenland Ice Sheet?s bed exposed to surface meltwater will increase substantially in a warming climate. The results of this research will be disseminated to the public through extensive ongoing efforts of these investigators including K-12 activities and public lectures. The direct involvement of a photographer-writer team will also bring a local dimension to understanding and communicating the impact of climate change on Greenland communities. Our results will also be of immediate interest to scientists working to understand past and future changes to the Greenland Ice Sheet, including theoretical and modeling studies. This project will also include direct graduate student involvement in field and research activities at both WHOI and UW.