基于小波分析的高空大气湍流相干结构特征研究

通过对风速脉动和温度脉动数据进行谱分析和小波分析，得到不同高度大气湍流相干结构尺度，用来同时识别时间序列中相干结构的特征尺度，并与大气折射率结构常数Cn2相结合分析高空大气湍流强弱分层的相干结构特征，提取不同高度湍流层强度、湍流层厚度等空间特征。通过研究发现，随着高度的变化，湍流呈现强弱分层交替出现的空间特征，且随高度升高，湍流持续时间变短，湍流层厚度也变小；在大尺度的弱湍流背景下存在小尺度强湍流，分布相对密集，持续时间较短，厚度也较小。高空大气湍流在5~15 km上的存在明显的强弱分层现象，在6~10 km高度上有四个强湍流层，湍流层厚度约为500 m。

Characteristics of Coherent Structures of Atmospheric Turbulence in High Latitude Based on Wavelet Analysis

Fluctuation dates of wind speed and temperature are analyzed by using spectral analysis and wavelet analysis. Then the coherent structures of atmospheric turbulence at different heights are obtained. They are used to identify the characteristic scales of coherent structures in time series. They are also used to extract spatial characteristics of coherent structures of atmospheric turbulence in high altitude by combining structural parameters of atmospheric refractive index Cn2, and the spatial characteristics like turbulence intensity and turbulent layer thickness were extracted. It is found that with the change of the height, the turbulence is manifested by the alternation of the strong stratification and the weak stratification. As the height increases, the turbulence duration becomes shorter and the thickness of the turbulent layer becomes smaller. Strong turbulences of small scale exist in weak turbulence of large scale. They have relatively dense distribution, short duration, and small thickness. The high altitude atmospheric turbulence in this measurement is found to have a clear phenomenon of strong or weak stratification in the 5 ~15 km. At the height of 6km-10km, there are four strong turbulence layers, and the thickness of the turbulent layer is about 500 m.