Characterizing bed roughness on the Antarctic continental margin
Characterizing bed roughness on the Antarctic continental margin
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DOI：
10.1017/jog.2023.88
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发表时间：
2023-10
影响因子：
3.4
通讯作者：
Santiago Munevar Garcia;Lauren E Miller;F. Falcini;Leigh A. Stearns
中科院分区：
文献类型：
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作者：
Santiago Munevar Garcia;Lauren E Miller;F. Falcini;Leigh A. Stearns
河床地形的空间变异（以河床粗糙度为特征）会影响冰盖的流动和组织，可用于推断冰下条件和过程，但由于观测稀疏而难以量化。整个南极大陆架上发现的先前扩张的冰川的古冰下床保存完好，冰河后沉积物覆盖相对有限，并且包含可以在亚米垂直尺度上解析的冰川地貌。我们分析了阿蒙森海松岛和思韦茨冰川近海的高分辨率测深，以探索河床粗糙度的空间变化，其中流线型的冰下地貌可以确定冰流方向。我们使用标准差来量化床粗糙度。和快速傅里叶变换方法，每种方法均在局部（100公里）和区域（101-2公里）尺度以及沿流和横流方向上使用，以确定跨空间尺度的粗糙度表达式。我们发现粗糙度的大小受到所选参数的影响（这些参数通常在研究中没有得到充分报告）来量化粗糙度。重要的空间模式可以从高分辨率测深中辨别出来，突出了它在识别流冰流模式方面的有用性，并强调了对表征地形变化的标准化方法的需要。
Spatial variability in bed topography, characterized as bed roughness, impacts ice-sheet flow and organization and can be used to infer subglacial conditions and processes, yet is difficult to quantify due to sparse observations. Paleo-subglacial beds of formerly expanded glaciers found across the Antarctic continental shelf are well preserved, have relatively limited post-glacial sediment cover and contain glacial landforms that can be resolved at sub-meter vertical scales. We analyze high-resolution bathymetry offshore of Pine Island and Thwaites glaciers in the Amundsen Sea to explore spatial variability of bed roughness where streamlined subglacial landforms allow for the determination of ice-flow direction. We quantify bed roughness using std dev. and Fast Fourier Transform methods, each employed at local (100 km) and regional (101–2 km) scales and in along- and across-flow orientations to determine roughness expressions across spatial scales. We find that the magnitude of roughness is impacted by the parameters selected – which are often not sufficiently reported in studies – to quantify roughness. Important spatial patterns can be discerned from high-resolution bathymetry, highlighting both its usefulness in identifying patterns of streaming ice flow and underscores the need for a standardized way of characterizing topographic variability.