Ice-flow perturbation analysis: a method to estimate ice-sheet bed topography and conditions from surface datasets
Ice-flow perturbation analysis: a method to estimate ice-sheet bed topography and conditions from surface datasets
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DOI：
10.1017/jog.2023.50
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发表时间：
2023-08
影响因子：
3.4
通讯作者：
Helen Ockenden;R. Bingham;Andrew Curtis;D. Goldberg
中科院分区：
文献类型：
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作者：
Helen Ockenden;R. Bingham;Andrew Curtis;D. Goldberg
冰盖模型预测海平面上升的最大不确定性因素之一是缺乏对冰盖下床层地形的了解。河床地形图通常是通过使用克里格法、质量守恒和流线扩散等方法在线性雷达测量之间进行插值来制作的，所有这些方法都可能会错过有影响力的中尺度（2-30公里）河床形态。之前的工作已经探索了冰流扰动分析（IFPA）方法，利用这些中尺度地床形态的表面表达来估计地床地形。使用已被透冰雷达密集勘察的松岛冰川区域作为测试点，并采用改进的 IFPA 方法，我们发现 IFPA 检测到能够影响冰流的床形，而 Bedmachine Antarctica 和其他插值床产品中没有出现这些床形。我们进一步探讨了 IFPA 估计相对河床滑度的能力，发现主干和支流的滑度较高。除了估计冰厚度的其他方法外，IFPA 的河床地形图也有可能限制对未来海平面上升的预测，特别是在雷达数据稀疏的情况下。
One of the largest contributors to uncertainty in predictions of sea-level rise from ice-sheet models is a lack of knowledge about the bed topography beneath ice sheets. Bed topography maps are normally made by interpolating between linear radar surveys using methods that include kriging, mass conservation and flowline diffusion, all of which may miss influential mesoscale (2–30 km) bedforms. Previous works have explored an Ice-Flow Perturbation Analysis (IFPA) approach for estimating bed topography using the surface expression of these mesoscale bedforms. Using regions of Pine Island Glacier that have been intensively surveyed by ice-penetrating radar as test sites, and a refined IFPA methodology, we find that IFPA detects bedforms capable of influencing ice flow which are not represented in Bedmachine Antarctica and other interpolated bed products. We further explore the ability of IFPA to estimate relative bed slipperiness, finding higher slipperiness in the main trunk and tributaries. Alongside other methods which estimate ice thickness, bed topography maps from IFPA have the potential to constrain projections of future sea-level rise, especially where radar data are sparse.