Characterization of subglacial marginal channels using 3-D analysis of high-density ground-penetrating radar data
Characterization of subglacial marginal channels using 3-D analysis of high-density ground-penetrating radar data
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使用高密度探地雷达数据的 3D 分析来表征冰下边缘通道
DOI：
10.1017/jog.2021.26
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发表时间：
2021
影响因子：
3.4
通讯作者：
S. Lane
中科院分区：
文献类型：
--
作者：
P. Egli;J. Irving;S. Lane
研究冰下水系网络对于理解冰下水系动力学与冰川快速退缩之间的潜在关系以及冰下水系在冰下沉积物排泄中的作用具有重要意义。为了描绘冰嘴边缘冰下通道的平面几何形状，在瑞士西南部阿尔卑斯山脉的两个温带冰川，Haut冰川d'Arolla和冰川d'Otemma的冰嘴边缘区域进行了密集间隔的频率为~70 MHz的探地雷达（GPR）测量。利用三维数据处理和沿冰川床的探地雷达反射幅值分析，绘制了河道图。在阿罗拉冰川（Haut Glacier d’arolla），发现了两条相对笔直的河道，宽度为几米。这些通道的位置与冰川末端的通道出口位置以及GPR数据采集一个月后冰川表面出现的裂缝位置吻合较好。后者被认为代表了冰下通道上方冰崩塌的开始。在奥德玛冰川，发现了一条主要的冰下管道，其尺寸与在阿罗拉冰川上发现的相似，但弯曲度更大。这条通道的位置是由冰川边缘崩塌后获得的无人机图像确认的。我们的研究结果证实，高密度三维探地雷达测量可以用于绘制温带高山冰川边缘附近的冰下通道。
Abstract Studying subglacial drainage networks is important for understanding the potential relationship between channel dynamics and rapid glacier recession as well as the role of subglacial channels in subglacial sediment evacuation. In order to delineate the planform geometry of snout marginal subglacial channels, densely spaced ground-penetrating radar (GPR) measurements at a frequency of ~70 MHz were carried out over the snout marginal zones of two temperate glaciers in the southwestern Swiss Alps, the Haut Glacier d'Arolla and the Glacier d'Otemma. Three-dimensional (3-D) data processing and amplitude analysis of the GPR reflection along the glacier bed was used to map the channels. At the Haut Glacier d'Arolla, two relatively straight channels of several meters in width were identified. The positions of these channels correspond well with the locations of channel outlets at the glacier terminus, as well as with fractures appearing on the glacier surface one month after the GPR data acquisition. The latter are believed to represent the beginning of ice collapse above the subglacial channels. At the Glacier d'Otemma, a major subglacial conduit was detected with similar dimensions to those identified at the Haut Glacier d'Arolla, but greater sinuosity. The position of this channel was confirmed by drone-based imagery acquired after glacier margin collapse. Our results confirm that high-density 3-D GPR surveys can be used to map subglacial channels near temperate alpine glacier margins.
漏斗状表面凹陷 â 冰川快速崩解的指标还是促进剂？
影响因子：
3.9
作者：
Stocker-Waldhuber;Fischer;Keller;Morche
通讯作者：
Morche