Momentum flux due to trapped lee waves forced by mountains
Momentum flux due to trapped lee waves forced by mountains
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由于山脉迫使背风波滞留而产生的动量通量
DOI：
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发表时间：
2002
期刊：
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通讯作者：
A. Broad
中科院分区：
文献类型：
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作者：
A. Broad
一个简单的，但一般的，无粘流的水平动量预算的发展，以了解如何在山区被迫被困的背风波列的水平动量的垂直通量随高度变化。取波场的正弦形式，从两层Scorer参数大气的解析解，流线上的常数伯努利泛函用于诊断动量通量。结果表明，在一个无粘，稳定的波列的动量通量的大小随高度的正弦函数。目前的理论清楚地表明，如何这个配置文件的动量通量与高度是一个直接的结果之间的精确平衡的垂直导数的动量通量和动态压力差在稳定状态下的山。通量随高度变化的简单解析剖面图与孤立山脊上理想情况下的数值模型结果具有显著的定性相似性。© Crown copyright，2002.
A simple, but general, horizontal momentum budget for inviscid flow is developed to understand how the vertical flux of horizontal momentum varies with height in a mountain‐forced trapped lee‐wave train. Taking a sinusoidal form for the wave field, from the analytical solution for a two‐layer Scorer‐parameter atmosphere, the constant Bernoulli functional on a streamline is used to diagnose the momentum flux. It is shown that in an inviscid, steady wave train the magnitude of the momentum flux decreases with height as a sinusoidal function. The present theory clearly shows how this profile of momentum flux with height is a direct consequence of the exact balance between the vertical derivative of momentum flux and the dynamic pressure difference across the mountain in steady state. The simple analytic profile of flux with height shows a remarkable qualitative similarity with numerical‐model results from idealized case‐studies of flow over an isolated mountain ridge. © Crown copyright, 2002.