Comparing numerical ice-sheet model output with radio-echo sounding measurements in the Weddell Sea sector of West Antarctica
Comparing numerical ice-sheet model output with radio-echo sounding measurements in the Weddell Sea sector of West Antarctica
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DOI：
10.1017/aog.2019.39
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发表时间：
2019-11
影响因子：
2.9
通讯作者：
H. Jeofry;N. Ross;M. Siegert
中科院分区：
文献类型：
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作者：
H. Jeofry;N. Ross;M. Siegert
摘要数值冰盖模型通常通过修改基底阻力来匹配来自干涉合成孔径雷达测量的表面冰速度，从而模拟冰盖的流动和形状。然而，很少使用床的地球物理测量来检查这种修改是否现实。在这里，我们检查无线电回波探测（RES）数据从南极洲西部的威德尔海部门调查如何从一个完善的冰盖模型的输出比较与测量的基础环境。我们知道威德尔海部分包含研究所，穆勒和基金会冰流，每一个都有不同的基础特征：研究所冰流部分位于潮湿的未固结沉积物上，那里的基础阻力非常低;穆勒冰流位于相对粗糙的床上，那里的基础阻力可能更大;基金会冰流受一个深的冰下槽控制，有流动的基岩地貌和光滑的未固结沉积物。总体而言，冰盖模式较好地反映了各冰流系统。我们还发现，冰的速度不完全匹配在某些位置，和调整边界的低基底阻力，以反映RES的证据，应提高模型的性能。我们的工作展示了有用的RES在校准冰盖模型的结果与观测的床。
Abstract Numerical ice-sheet models are commonly matched to surface ice velocities from InSAR measurements by modifying basal drag, allowing the flow and form of the ice sheet to be simulated. Geophysical measurements of the bed are rarely used to examine if this modification is realistic, however. Here, we examine radio-echo sounding (RES) data from the Weddell Sea sector of West Antarctica to investigate how the output from a well-established ice-sheet model compares with measurements of the basal environment. We know the Weddell Sea sector contains the Institute, Möller and Foundation ice streams, each with distinct basal characteristics: Institute Ice Stream lies partly over wet unconsolidated sediments, where basal drag is very low; Möller Ice Stream lies on relatively rough bed, where basal drag is likely larger; and Foundation Ice Stream is controlled by a deep subglacial trough with flow-aligned bedrock landforms and smooth unconsolidated sediments. In general, the ice-sheet model represents each ice-stream system well. We also find that ice velocities do not match perfectly in some locations, and that adjustment of the boundaries of low basal drag, to reflect RES evidence, should improve model performance. Our work showcases the usefulness of RES in calibrating ice-sheet model results with observations of the bed.