Nonstationary Trapped Lee Waves Generated by the Passage of an Isolated Jet
Nonstationary Trapped Lee Waves Generated by the Passage of an Isolated Jet
复制标题
孤立射流通过时产生的非稳态截留李波
DOI：
10.1175/jas-d-12-047.1
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发表时间：
2012
影响因子：
3.1
通讯作者：
D. Durran
中科院分区：
文献类型：
--
作者：
M. Hills;D. Durran
摘要用理想化三维数值模拟方法研究了非定常背景流中非定常捕获背风波的行为。孤立的天气尺度正压急流通过有限长度的山脊，强迫捕获的波。与通常研究的二维(2D)定常流动中的波相比，在这种环境中产生的捕获波的行为有很大的不同。峰值纬向流穿过地形后，在成熟的波列中形成两个不同的区域：1)急流极大值的上风，捕获波的波长增加，并趋于解禁和衰减；2)急流极大值的下风，波长缩短，波仍被捕获。海浪开始在脊顶下风向约100公里处解困，解困区域随着急流的推进而在顺风向扩展，而急流最大值下游的海浪则持续存在。Wentzel-Kramers-Brillouin(WKB)射线追迹表明，空间梯度...
AbstractThe behavior of nonstationary trapped lee waves in a nonsteady background flow is studied using idealized three-dimensional (3D) numerical simulations. Trapped waves are forced by the passage of an isolated, synoptic-scale barotropic jet over a mountain ridge of finite length. Trapped waves generated within this environment differ significantly in their behavior compared with waves in the more commonly studied two-dimensional (2D) steady flow. After the peak zonal flow has crossed the terrain, two disparate regions form within the mature wave train: 1) upwind of the jet maximum, trapped waves increase their wavelength and tend to untrap and decay, whereas 2) downwind of the jet maximum, wavelengths shorten and waves remain trapped. Waves start to untrap approximately 100 km downwind of the ridge top, and the region of untrapping expands downwind with time as the jet progresses, while waves downstream of the jet maximum persist. Wentzel–Kramers–Brillouin (WKB) ray tracing shows that spatial gradien...