Possible erosion mechanisms in snow avalanches
Possible erosion mechanisms in snow avalanches
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DOI：
10.3189/172756404781815068
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发表时间：
2004-01-01
期刊：
影响因子：
--
通讯作者：
Issler, D
中科院分区：
文献类型：
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作者：
Gauer, P;Issler, D
雪崩中的雪侵蚀和卷吸过程根据其机制、它们发生的流态以及它们在雪崩中的空间位置进行分类。简单，但具体过程中，模型提出的影响，磨损，犁和爆破的侵蚀。根据数量级估计，前三种机制显然很重要。第四种机制规定，雪崩前积雪的压实导致雪崩前的逃逸空气流动，这可能会破坏积雪并支持跳跃层的形成。这种假设机制的效果类似于犁耕机制的效果。所有的机制强烈依赖于雪的属性，但是，合理的参数值，侵蚀率或以上的实验发现率。所有雪崩的卷吸率通常受到将侵蚀雪加速到雪崩速度所需的剪应力的限制。
Snow erosion and entrainment processes in avalanches are classified according to their mechanisms, the flow regimes in which they occur, and their spatial position within the avalanche. Simple, but process-specific, models are proposed for erosion by impacts, abrasion, plowing and blasting. On the basis of order-of-magnitude estimates, the first three mechanisms are clearly expected to be important. The fourth mechanism stipulates that the compaction of the snow cover ahead of the avalanche leads to the flow of escaping air just in front of the avalanche that may disrupt the snow cover and support formation of a saltation layer. The effects of this hypothetical mechanism resemble those of the plowing mechanism. All mechanisms depend strongly on the snow properties, but, with plausible parameter values, erosion rates at or above the experimentally found rates are obtained. The entrainment rate of all avalanche is most often limited by the shear stress needed to accelerate the eroded snow to avalanche speed.