大气相干长度测量实验与分析

Measurement Experiment and Analysis of Atmospheric Coherence Length

大气相干长度是对大气湍流介质进行定量描述的重要参量之一。介绍光强闪烁法和到达角起伏方差法反演大气相干长度两种不同测量方法。在相距893m的水平路径上进行激光大气传输实验,每隔10分钟对数据进行采样,计算出光强闪烁指数和到达角起伏方差。在弱湍流情况下,利用光强闪烁指数和达到角起伏方差反演大气相干长度。实验结果表明两种测量方法存在一定差异,但总体趋势保持一致,但秋季与夏季的趋势不一致,并对两种测量方式产生误差的原因进行了分析。

The atmospheric coherence length is one of most important parameters of atmospheric propagation of laser. The means of atmospheric coherence length measurement inferred by measuring the optical wave’s angle-of-arrival （AOA） fluctuation and the measurement method deduced from the irradiance scintillation of laser propagation are de-scribed. A measurement experiment of atmospheric propagation of laser is conducted along the longitudinal path with 893 meters apart. The experimental sample frequency of data acquisitions is 10 minutes. The fluctuation variance of irra-diance scintillation and AOA are computed based on the data. Under weak turbulence,the atmospheric coherence length is computed using irradiance scintillation fluctuation variance and AOA fluctuation variance respectively. Some differences exist between the two methods,but the overall trend remains the same. The results differ in autumn and summer. Er-ror reason of the differences is analyzed.