Christoffersen Poul, Bougamont Marion, Hubbard Alun, Doyle Samuel H, Grigsby Shane, Pettersson Rickard
Scott Polar Research Institute, University of Cambridge, Cambridge, CB2 1ER, UK.
Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, The Arctic University of Norway, N-9037, Tromsø, Norway.
Nat Commun. 2018 Mar 14;9(1):1064. doi: 10.1038/s41467-018-03420-8.
Supraglacial lakes on the Greenland Ice Sheet are expanding inland, but the impact on ice flow is equivocal because interior surface conditions may preclude the transfer of surface water to the bed. Here we use a well-constrained 3D model to demonstrate that supraglacial lakes in Greenland drain when tensile-stress perturbations propagate fractures in areas where fractures are normally absent or closed. These melt-induced perturbations escalate when lakes as far as 80 km apart form expansive networks and drain in rapid succession. The result is a tensile shock that establishes new surface-to-bed hydraulic pathways in areas where crevasses transiently open. We show evidence for open crevasses 135 km inland from the ice margin, which is much farther inland than previously considered possible. We hypothesise that inland expansion of lakes will deliver water and heat to isolated regions of the ice sheet's interior where the impact on ice flow is potentially large.
格陵兰冰原上的冰上湖泊正在向内陆扩张，但对冰流的影响并不明确，因为内部表面条件可能会阻止地表水向冰床的转移。在这里，我们使用一个约束良好的三维模型来证明，当拉应力扰动在通常不存在或闭合裂缝的区域传播裂缝时，格陵兰的冰上湖泊会排水。当相距80公里的湖泊形成广阔的网络并迅速相继排水时，这些由融化引起的扰动会加剧。结果是产生一个拉伸冲击，在裂缝暂时打开的区域建立新的从表面到冰床的水力通道。我们展示了距离冰缘内陆135公里处存在开放裂缝的证据，这比之前认为可能的距离要远得多。我们推测，湖泊的内陆扩张将把水和热量输送到冰原内部的孤立区域，在这些区域对冰流的影响可能很大。
