On the extraction of turbulent parameters from atmospheric density fluctuations
On the extraction of turbulent parameters from atmospheric density fluctuations
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大气密度涨落中湍流参数的提取
DOI：
10.1029/92jd01916
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发表时间：
1992
影响因子：
--
通讯作者：
F. Lübken
中科院分区：
文献类型：
--
作者：
F. Lübken
分析位势中性密度等标量示踪剂的湍流涨落的标准方法是从光谱中获得结构函数常数C2n，并由C2n推导出地球物理相关参数。正如前面已经认识到的，这种方法有一个显著的缺点，因为需要一些非常难以测量的“常量”，因此这些“常量”知之甚少。此外，文献中也出现了所用常量的不一致之处。在本文中，我们提出了一种从谱中获得湍流参数的新方法，在这些谱中，大多数“常数”是不需要的。其基本思想是将光谱模型[Tatarskii，1971]与实验光谱相适应，该光谱既包括惯性对流，也包括到粘性扩散子区的过渡。将这种新方法应用于NLC-91和Dyana战役期间的光谱，结果表明，模型与数据符合得很好。从C2n和光谱模型获得的能量耗散率的示例性比较显示，后者的值较大，其中一种情况的差异相对较小(DAT13，系数1.2)，第二次飞行的偏差较大(NBT5，系数2.4)。
A standard method to analyze turbulent fluctuations of a scalar tracer such as potential neutral density is to obtain the structure function constant C2n from the spectrum and to deduce geophysical relevant parameters from C2n. As has been realized earlier, there is a significant drawback in this method because some “constants” are needed which are very difficult to measure and which are therefore only poorly known. In addition, inconsistencies in the constants used also appeared in the literature. In this paper we present a new method to obtain turbulent parameters from the spectra where most of these “constants” are not needed. The basic idea is to fit a spectral model [Tatarskii, 1971] to the experimental spectrum which comprises both the inertial-convective and the transition to the viscous-diffusive subrange. Application of this new method to spectra during the NLC-91 and DYANA campaign shows good agreement between the model and the data. Exemplary comparison of the energy dissipation rates obtained from C2n and from the spectral model shows larger values for the latter with comparatively small difference in one case (DAT13, factor 1.2) and larger deviations in a second flight (NBT5, factor 2.4).