Wavelet analysis of stratospheric gravity wave packets over Macquarie Island 2. Intermittency and mean-flow accelerations
Wavelet analysis of stratospheric gravity wave packets over Macquarie Island 2. Intermittency and mean-flow accelerations
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DOI：
10.1029/2000jd900846
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发表时间：
2001-05
影响因子：
--
通讯作者：
F. Zink;R. Vincent
中科院分区：
文献类型：
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作者：
F. Zink;R. Vincent
本文计算了1994年2月至1995年4月在麦夸里岛（55°S，159°E）平流层下部观测到的重力波波包引起的平均气流加速度。波包参数是使用Zink和Vincent [本期]提出的基于小波的分析方法从每天两次的无线电探空中提取的。推导出的波参数被用来直接计算在平流层下部的动量通量廓线，这种方法来评估平均流加速度的缺点进行了讨论。然后，我们使用所观察到的波包作为线性射线跟踪模型的输入频谱。检测到的波包的垂直范围，使我们能够定义一个表达式的波的折射率，这使我们能够计算在平流层和中间层的纬向加速度。在平流层中，波产生平均流的加速，与预测一致。在中间层，推断的波阻比以前的观测和理论估计大2-3倍。
We calculate the mean-flow accelerations due to gravity wave packets observed in the lower stratosphere over Macquarie Island (55°S, 159°E) between February 1994 and April 1995. The parameters of the wave packets were extracted from twice-daily radiosonde soundings using a wavelet-based analysis method introduced by Zink and Vincent [this issue]. The deduced wave parameters are used to directly compute momentum flux profiles in the lower stratosphere, and the shortcomings of this approach to assess mean-flow accelerations are discussed. We then use the observed wave packets as an input spectrum in a linear ray-tracing model. The vertical extent of the detected wave packets allows us to define an expression for wave intermittency, which enables us to compute zonal accelerations in the stratosphere and mesosphere. In the stratosphere the waves produce an acceleration of the mean flow, in accordance with predictions. In the mesosphere the inferred wave drag is 2–3 times larger than previous observational and theoretical estimates.