Ice stream formation
Ice stream formation
复制标题
冰流形成
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
E. Mantelli
中科院分区：
文献类型：
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作者：
C. Schoof;E. Mantelli
冰流是冰盖中快速流动的冰带。我们以耗散和基底滑动之间的正反馈为基础，将其形成作为自发模式形成的一个例子进行研究。我们的重点是与温度相关的亚温带滑动，在这种情况下，更快的滑动会导致耗散增加，从而温度升高，使基底进一步弱化，尽管我们也研究了一种在完全融化的基底上起作用的流体力学反馈机制。我们开发了一种新的热机械模型，该模型在横向捕捉冰厚尺度的物理现象，同时假设在主要下游方向流动是浅的。利用该模型，我们表明，通过在下游方向放大嘈杂的基底条件，可以形成一种随时间稳定的模式，并且常常导致形成一条明确界定的冰流，它通过狭窄的剪切边缘与缓慢流动的、以寒冷为基底的冰脊分开，冰流在下游方向变宽。我们能够表明，冷冰的向下平流是主要的稳定机制，并给出了模式形成的一个近似的分析判据。
Ice streams are bands of fast-flowing ice in ice sheets. We investigate their formation as an example of spontaneous pattern formation, based on positive feedbacks between dissipation and basal sliding. Our focus is on temperature-dependent subtemperate sliding, where faster sliding leads to enhanced dissipation and hence warmer temperatures, weakening the bed further, although we also treat a hydromechanical feedback mechanism that operates on fully molten beds. We develop a novel thermomechanical model capturing ice-thickness scale physics in the lateral direction while assuming the the flow is shallow in the main downstream direction. Using that model, we show that formation of a steady-in-time pattern can occur by the amplification in the downstream direction of noisy basal conditions, and often leads to the establishment of a clearly-defined ice stream separated from slowly-flowing, cold-based ice ridges by narrow shear margins, with the ice stream widening in the downstream direction. We are able to show that downward advection of cold ice is the primary stabilizing mechanism, and give an approximate, analytical criterion for pattern formation.
影响因子：
5.2
作者：
Holschuh, N.;Lilien, D. A.;Christianson, K.
通讯作者：
Christianson, K.