Digital surface models are not always representative of former glacier beds: Palaeoglaciological and geomorphological implications
Digital surface models are not always representative of former glacier beds: Palaeoglaciological and geomorphological implications
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DOI：
10.1016/j.geomorph.2013.03.026
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发表时间：
2013-07-15
期刊：
影响因子：
3.9
通讯作者：
Finlayson, Andrew
中科院分区：
文献类型：
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作者：
Finlayson, Andrew
使用数字表面模型（DSM）的定量古冰川学研究可能会出现错误，因为以前的冰川床并不总是准确的代表。这是因为地球表面自冰川消退以来可能发生了重大变化。本文评估了一些潜在的错误所造成的冰后期沉积，通过比较物理palaeglaciological重建和床形形态分析的结果在苏格兰的部分地区，使用现代的陆地表面和插值前冰川床钻孔数据。对于一个前陆地出口冰川，去除冰后期沉积物增加了0.7%和5%，分别超过27公里的流线模拟冰面海拔和冰厚度。对于一个前冰川，重建的稳态冰通量增加了250%，当现代的陆地/海底表面被替换为内插前冰川床。在一个经典的drumlinised景观，去除冰后期沉积物影响床形形态，增加了测量drumlin长度，宽度，浮雕和体积。本文介绍的案例来自已知经历过冰后期沉积的环境。它们提供了在这些环境中使用现代地表来代表前冰川床时可能引入的误差程度的情景示例。在某些区域，大面积地下数据充足，可以更好地描绘前冰川床的地形;这些数据可以成为下一代古冰盖和古冰川模拟的重要投入。(C)2013年自然环境研究理事会。Elsevier B. V.出版，保留所有权利。
Quantitative palaeoglaciological studies that use digital surface models (DSMs) may be subject to error because former glacier beds are not always accurately represented. This is because the Earth's surface may have changed significantly since deglaciation. This paper evaluates some of the potential errors caused by postglacial sedimentation, by comparing the results of physical palaeoglaciological reconstructions and bedform morphometric analyses in parts of Scotland, using both the modern land surface and interpolated former glacier beds derived from borehole data. For a former terrestrial outlet glacier, removal of postglacial sediments increases the modelled ice surface elevation and ice thickness by 0.7% and 5%, respectively, over a 27-km flow line. For a former tidewater glacier, the reconstructed steady state ice flux is increased by 250% when the modern land/seabed surface is replaced with an interpolated former glacier bed. In a classical drumlinised landscape, removal of postglacial sediments affects bedform morphometrics, with an increase in measured drumlin length, width, relief, and volume. The cases presented in this paper are from environments known to have experienced postglacial sedimentation. They provide situational examples of the degree of error that can be introduced when the modern land surface is used to represent former glacier beds in these environments. In some regions, sufficient subsurface data exists over large areas to create improved topographic representations of former glacier beds; these could form important inputs to the next generation of palaeo-ice-sheet and palaeo-glacier simulations. (C) 2013 Natural Environment Research Council. Published by Elsevier B.V. All rights reserved.