Firn aquifer water discharges into crevasses across Southeast Greenland
Firn aquifer water discharges into crevasses across Southeast Greenland
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DOI：
10.1017/jog.2023.25
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发表时间：
2023-05
影响因子：
3.4
通讯作者：
Eric Cicero;K. Poinar;R. Jones-Ivey;A. Petty;Jeanette M. Sperhac;A. Patra;J. Briner
中科院分区：
文献类型：
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作者：
Eric Cicero;K. Poinar;R. Jones-Ivey;A. Petty;Jeanette M. Sperhac;A. Patra;J. Briner
在格陵兰岛东南部，夏季的融化和冬季的高降雪率导致了积雪含水层的形成：大量的融水埋在冰盖表面之下。以前对格陵兰单一的积雪含水层进行的详细研究表明，水流入裂缝，但在区域范围内还不清楚。我们开发和使用一个工具，在Ghub，共享数据集，工具和超级计算资源的冰川学的在线网关，以确定裂缝从海拔数据收集的美国宇航局的机载地形测绘仪横跨29000平方公里的格陵兰岛东南部。我们发现裂缝3公里内的先前绘制的冰川下边界的积雪含水层在20的25个飞行路线交叉。我们的数据表明，裂缝扩大，直到他们到达冰川的积雪含水层的下行边界，这意味着裂缝收集积雪含水层的水，但我们没有发现这种趋势与统计意义。裂缝宽度中位数为27米，这意味着裂缝到达河床的纵横比是一致的。我们的研究结果支持的想法，大部分水在格陵兰东南部的积雪含水层通过裂缝排水。不太常见的结果是冰盖表面的排放（25个地点中的3个）和含水层底部的重新冻结（25个地点中的1个）。
Abstract In Southeast Greenland, summer melt and high winter snowfall rates give rise to firn aquifers: vast stores of meltwater buried beneath the ice-sheet surface. Previous detailed studies of a single Greenland firn aquifer site suggest that the water drains into crevasses, but this is not known at a regional scale. We develop and use a tool in Ghub, an online gateway of shared datasets, tools and supercomputing resources for glaciology, to identify crevasses from elevation data collected by NASA's Airborne Topographic Mapper across 29000 km2 of Southeast Greenland. We find crevasses within 3 km of the previously mapped downglacier boundary of the firn aquifer at 20 of 25 flightline crossings. Our data suggest that crevasses widen until they reach the downglacier boundary of the firn aquifer, implying that crevasses collect firn-aquifer water, but we did not find this trend with statistical significance. The median crevasse width, 27 meters, implies an aspect ratio consistent with the crevasses reaching the bed. Our results support the idea that most water in Southeast Greenland firn aquifers drains through crevasses. Less common fates are discharge at the ice-sheet surface (3 of 25 sites) and refreezing at the aquifer bottom (1 of 25 sites).