Antarctic ice streams: a review
Antarctic ice streams: a review
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南极冰流：回顾
DOI：
10.1029/jb092ib09p08843
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发表时间：
1987
影响因子：
--
通讯作者：
C. Bentley
中科院分区：
文献类型：
--
作者：
C. Bentley
冰流是内陆冰盖的一部分，它快速地流过周围的冰。冰盖和出口冰川之间的区别在原则上是明确的，但在实践中是模糊的-许多南极冰川在性质上是中间的。罗斯冰流（英语：Ross ice streams）是从南极洲西部的内陆冰流入罗斯冰架的冰流，其特征是独特的，甚至与南极洲西部海洋冰盖的其他冰流不同。它们的表面高程剖面较低，河床坡度较低且平滑，驱动应力沿冰川向下单调减小。在横向剖面上，它们比其他冰流更宽，冰下槽也更浅。许多冰川快速滑动的模型都被应用于罗斯冰流;大多数模型都以某种形式包括了底部阻力的减少，这是由于底部的有效压力低于冰川静压力。大多数模型充其量只是半物理的，因此需要通过拟合真实的冰盖中某个或某些地方的假设参数来“调整”。最近发现的一个冰流下的一个非常小的有效压力，从而导致了一些严重的错误，在速度预测的模型。最近的实验表明，如果冰流B以及其他罗斯冰流在变形的河床上滑动，而该河床吸收了冰和基岩之间的大部分或全部差异运动，那么这个难题就可以解决。
An ice stream is a part of an inland ice sheet that flows rapidly through the surrounding ice. The distinction between an ice sheet and an outlet glacier is clear in principle but muddy in practice -- many Antarctic glaciers are intermediate in character. The “Ross ice streams,” which flow through the West Antarctic inland ice into the Ross Ice Shelf, are distinct in character, differing even from other ice streams in the marine ice sheet of West Antarctica. Their surface elevation profiles are low, their bed slopes are low and smooth, and their driving stresses diminish monotonically downglacier. In transverse profile they are broader in relation to ice thickness and exhibit shallower subglacial troughs, than other ice streams. Many models for the fast sliding of glaciers have been applied to the Ross ice streams; most have included in some form a reduction in basal drag resulting from a lesser effective than glaciostatic pressure at the bed. Most models are only semi physical at best, so need to be “tuned” by fitting to assumed parameters at some place or places in the real ice sheet. The recent discovery of a very small effective pressure beneath one ice stream consequently has led to some gross errors in the velocities predicted by the models. The difficulty may be resolved if it is true, as recent experiments suggest, that ice stream B, and by extrapolation other Ross ice streams as well, slide on a deforming bed that absorbs most or all of the differential motion between the ice and the bedrock.