The Role of Ambient Turbulence in Canopy Wave Generation by Kelvin–Helmholtz Instability
The Role of Ambient Turbulence in Canopy Wave Generation by Kelvin–Helmholtz Instability
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DOI：
10.1007/s10546-022-00765-y
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发表时间：
2023-01
影响因子：
4.3
通讯作者：
W. Smyth;S. Mayor;Q. Lian
中科院分区：
文献类型：
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作者：
W. Smyth;S. Mayor;Q. Lian
我们测试的假设，观察到的森林冠层流内波产生的开尔文-亥姆霍兹不稳定性。在夜间，稳定分层和弱风条件下，水平扫描气溶胶激光雷达和仪器塔观察到的波。激光雷达图像被用来确定每个情节的显着波长和相位传播速度。在塔上测量的时间序列数据，然后用于形成垂直剖面的背景速度和浮力就在每个观察到的波浪事件。将这些剖面输入Taylor-Goldstein方程，预测了增长最快的线性不稳定性的相速度、波长和周期，并将结果与激光雷达观测结果进行了比较。观测到的波长往往比泰勒-戈尔茨坦理论预测的要长，通常是两倍。当理论扩展到考虑周围小尺度湍流的影响时，这种差异就消除了。
We test the hypothesis that internal waves observed in flow over forest canopies are generated by Kelvin–Helmholtz instability. The waves were observed at night, under stably stratified and weak wind conditions, with a horizontally scanning aerosol lidar and an instrumented tower. The lidar images are used to determine the salient wavelength and phase propagation velocity of each episode. Time series data measured at the tower are then used to form vertical profiles of background velocity and buoyancy just before each observed wave event. The profiles are input to the Taylor–Goldstein equation to predict the phase velocity, wavelength and period of the fastest-growing linear instability, and the results compared with the lidar observations. The observed wavelengths tend to be longer than predicted by the Taylor–Goldstein theory, typically by a factor of two. That discrepancy is removed when the theory is extended to account for the effects of ambient, small-scale turbulence.