Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet
Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet
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南极冰盖边缘下露出深邃的冰川槽和稳定山脊
DOI：
10.1038/s41561-019-0510-8
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发表时间：
2020-02-01
影响因子：
18.3
通讯作者：
Young, Duncan A.
中科院分区：
文献类型：
--
作者：
Morlighem, Mathieu;Rignot, Eric;Young, Duncan A.
在过去的几十年里，南极冰盖由于受海洋温度和河床地形的影响，冰川加速流动，质量一直在减少。冰川沿着逆行斜坡后退（即河床高程向内陆方向下降）可能不稳定，而冰下山脊减缓了冰川后退。尽管在冰下河床地形测绘方面取得了重大进展，但南极洲的重要部分仍然没有得到很好的解决，关键的空间细节缺失。在这里，我们提出了一个新的，高分辨率和物理为基础的描述南极床地形质量守恒。我们的研究结果揭示了以前未知的基础功能与冰川对气候变化的反应的重大影响。例如，横贯南极山脉的冰川受到宽阔、稳定的山脊的保护。相反，在威尔克斯地，南极洲东部的海洋盆地，我们发现逆行斜坡沿着宁尼斯和登曼冰川，稳定斜坡下莫斯科大学，Totten和兰伯特冰川系统，尽管校正床海拔高达1公里，后者。这种对海床地形的变革性描述重新定义了南极海平面快速上升的高风险和低风险区域;它还将对未来几个世纪南极海平面上升的模型预测产生重大影响。
The Antarctic ice sheet has been losing mass over past decades through the accelerated flow of its glaciers, conditioned by ocean temperature and bed topography. Glaciers retreating along retrograde slopes (that is, the bed elevation drops in the inland direction) are potentially unstable, while subglacial ridges slow down the glacial retreat. Despite major advances in the mapping of subglacial bed topography, significant sectors of Antarctica remain poorly resolved and critical spatial details are missing. Here we present a novel, high-resolution and physically based description of Antarctic bed topography using mass conservation. Our results reveal previously unknown basal features with major implications for glacier response to climate change. For example, glaciers flowing across the Transantarctic Mountains are protected by broad, stabilizing ridges. Conversely, in the marine basin of Wilkes Land, East Antarctica, we find retrograde slopes along Ninnis and Denman glaciers, with stabilizing slopes beneath Moscow University, Totten and Lambert glacier system, despite corrections in bed elevation of up to 1 km for the latter. This transformative description of bed topography redefines the high- and lower-risk sectors for rapid sea level rise from Antarctica; it will also significantly impact model projections of sea level rise from Antarctica in the coming centuries.