Lee Waves on the Boundary-Layer Inversion and Their Dependence on Free-Atmospheric Stability
Lee Waves on the Boundary-Layer Inversion and Their Dependence on Free-Atmospheric Stability
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DOI：
10.3389/feart.2015.00070
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发表时间：
2015-11
影响因子：
2.9
通讯作者：
Johannes Sachsperger;S. Serafin;V. Grubišić
中科院分区：
文献类型：
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作者：
Johannes Sachsperger;S. Serafin;V. Grubišić
本研究探讨重力波，发展在边界层盖逆温在背风的山脊。通过比较不同的线性波理论，我们表明，在这些条件下形成的背风波最准确地描述为强迫界面波。在这种类型的流的扰动可以研究与线性二维模型与恒定的风速和一个尖锐的密度不连续分离两层，一个中性的下面和一个稳定的上面。在马德拉群岛的观测的基础上定义的模型参数，我们强调的界面波上层稳定性的影响。我们证明了高空稳定层结限制了背风波长的可能范围，并调制了驻波模式的长度。最后，我们表明，高层的稳定层结强烈约束的有效性浅水（或长波）近似只允许短波模式被困在界面上。
This study examines gravity waves that develop at the boundary-layer capping inversion in the lee of a mountain ridge. By comparing different linear wave theories, we show that lee waves that form under these conditions are most accurately described as forced interfacial waves. Perturbations in this type of flow can be studied with a linear two-dimensional model with constant wind speed and a sharp density discontinuity separating two layers, a neutral one below and a stable one above. Defining the model parameters on the basis of observations taken in the Madeira archipelago, we highlight the impact of upper-level stability on interfacial waves. We demonstrate that stable stratification aloft limits the possible range of lee wavelengths and modulates the length of the stationary wave mode. Finally, we show that the stable stratification aloft strongly constrains the validity of the shallow-water (or long-wave) approximation by permitting only short-wave modes to be trapped at the interface.