Seasonal evolution of subglacial drainage and acceleration in a Greenland outlet glacier
Seasonal evolution of subglacial drainage and acceleration in a Greenland outlet glacier
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DOI：
10.1038/ngeo863
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发表时间：
2010-06-01
影响因子：
18.3
通讯作者：
Sole, Andrew
中科院分区：
文献类型：
--
作者：
Bartholomew, Ian;Nienow, Peter;Sole, Andrew
格陵兰冰盖所含的水足以使海平面上升7米。然而，其目前的质量平衡和未来对海平面上升的贡献知之甚少（1）。在冰盖边缘附近观察到加速的质量损失，部分原因是冰的运动速度加快（2-4）。表面融化的沃茨可以到达冰盖的底部，并增强底部冰的运动（5，6）。然而，冰运动的季节性变化的融水供应的响应是不受限制的空间和时间。在这里，我们提出了冰的运动数据与全球定位系统接收器位于沿着一个类似的35公里的样带在格陵兰冰盖的西部边缘整个夏季融化季节。我们的测量结果显示，在夏季冰速度大幅增加，高达220%以上的冬季背景值。这些加速事件在整个夏季沿着冰川向上迁移。融化和冰运动之间的关系在整个融化季节的每个站点和站点之间都有所不同。我们认为，这些模式可以解释的冰下排水系统的季节性演变类似的水力强迫机制，已在较小的冰川冰动力学。
The Greenland ice sheet contains enough water to raise sea levels by 7 m. However, its present mass balance and future contribution to sea level rise is poorly understood(1). Accelerated mass loss has been observed near the ice sheet margin, partly as a result of faster ice motion(2-4). Surface melt waters can reach the base of the ice sheet and enhance basal ice motion(5,6). However, the response of ice motion to seasonal variations in meltwater supply is poorly constrained both in space and time. Here we present ice motion data obtained with global positioning system receivers located along a similar to 35 km transect at the western margin of the Greenland ice sheet throughout a summer melt season. Our measurements reveal substantial increases in ice velocity during summer, up to 220% above winter background values. These speed-up events migrate up the glacier over the course of the summer. The relationship between melt and ice motion varies both at each site throughout the melt season and between sites. We suggest that these patterns can be explained by the seasonal evolution of the subglacial drainage system similar to hydraulic forcing mechanisms for ice dynamics that have been observed at smaller glaciers.