Program in Atmospheric and Oceanic Sciences, Princeton University, 201 Forrestal Road. Princeton, NJ 08540, USA.
Science. 2013 Nov 29;342(6162):1086-9. doi: 10.1126/science.1243903. Epub 2013 Nov 7.
Fast-flowing glaciers and ice streams are pathways for ice discharge from the interior of the Antarctic Ice Sheet to ice shelves, at rates controlled by conditions at the ice-bed interface. Using recently compiled high-resolution data sets and a standard inverse method, we computed basal shear stress distributions beneath Pine Island and Thwaites Glaciers, which are currently losing mass at an accelerating rate. The inversions reveal the presence of riblike patterns of very high basal shear stress embedded within much larger areas with zero basal shear stress. Their colocation with highs in the gradient of hydraulic potential suggests that subglacial water may control the evolution of these high-shear-stress ribs, potentially causing migration of the grounding line by changes in basal resistance in its vicinity.
快速流动的冰川和冰流是南极冰盖内部的冰排放到冰架的途径，其排放速度由冰床界面的条件控制。利用最近编制的高分辨率数据集和标准反演方法，我们计算了目前以加速速率损失质量的派恩岛和思韦茨冰川下的基底剪切应力分布。反演结果显示，在基底剪切应力为零的较大区域内存在着基底剪切应力极高的肋状模式。这些模式与水力势梯度的高点重合，表明冰下水可能控制着这些高剪切应力肋的演化，从而可能通过改变附近的基底阻力来导致基线的迁移。
