Surface Expression of Basal and Englacial Features, Properties, and Processes of the Greenland Ice Sheet
Surface Expression of Basal and Englacial Features, Properties, and Processes of the Greenland Ice Sheet
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DOI：
10.1029/2018gl080620
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
M. Cooper;Thomas M. Jordan;M. Siegert;J. Bamber
中科院分区：
文献类型：
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作者：
M. Cooper;Thomas M. Jordan;M. Siegert;J. Bamber
测量格陵兰岛冰厚度的雷达探测调查使人们对基础地形和冰川过程有了越来越“完整”的了解。在此类观测受到空间限制的情况下，可以通过质量守恒或克里金法对河床高程进行插值。然而，普通克里金法无法解决冰床几何形状的各向异性，导致冰盖床高程模型中复杂的地形被错误地表示。在这里，我们展示了新的高分辨率（≤5 m）表面形貌数据（ArcticDEM）的潜力，可以增强对基底和冰川几何和过程的洞察力。通过残余表面高程量化的显着表面特征与记录的冰下河道一致，并且可以清楚地识别出新的较小规模支流（宽度<2,000 m）和山谷状结构。残余表面高程还可以绘制基底冰单元的范围，结合雷达数据表明它们充当“虚假底部”，这可能是由于冰柱的流变对比所致。
Radar‐sounding surveys measuring ice thickness in Greenland have enabled an increasingly “complete” knowledge of basal topography and glaciological processes. Where such observations are spatially limited, bed elevation has been interpolated through mass conservation or kriging. Ordinary kriging fails to resolve anisotropy in bed geometry, however, leaving complex topography misrepresented in elevation models of the ice sheet bed. Here, we demonstrate the potential of new high‐resolution (≤5 m) surface topography data (ArcticDEM) to provide enhanced insight into basal and englacial geometry and processes. Notable surface features, quantified via residual surface elevation, are observed coincident with documented subglacial channels, and new, smaller‐scale tributaries (<2,000 m in width) and valley‐like structures are clearly identified. Residual surface elevation also allows the extent of basal ice units to be mapped, which in conjunction with radar data indicate that they act as “false bottoms,” likely due to a rheological contrast in the ice column.