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

与格陵兰湖泊排水有关的水力破裂事件产生了表面到床的管道，表面熔体通过这些管道到达床上，速率从夏季长时间的熔体流动到突然的湖泊排水期间的大而瞬时的脉冲。虽然最近的研究表明，加强的季节性润滑对格陵兰冰盖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没有得到很好的约束，其影响在当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有一个坚实的物理基础的了解，并通过描述季节性和年际时间尺度上表面融化对冰盖流动的影响，来促进改善未来海平面上升的评估。这一知识的获得是将地表融化增加的影响整合到由模型得出的海平面预测中的重要一步。研究人员将使用地面和卫星综合观测的实验设计，结合数值模型来确定控制水力压裂的过程，并利用这一理解来确定在气候变暖的情况下，暴露在表面融化水中的格陵兰冰盖-S床的面积是否会大幅增加。这项研究的结果将通过这些调查人员正在进行的广泛努力向公众传播，包括K-12活动和公开讲座。摄影师-作家小组的直接参与还将带来一个当地层面，以了解和传播气候变化对格陵兰社区的影响。我们的结果也将立即引起致力于了解格陵兰冰盖过去和未来变化的科学家的兴趣，包括理论和模型研究。该项目还将包括研究生直接参与世界卫生组织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.