利用Kolmogorov谱、修正Hill谱和Rytov改进模型三种大气湍流功率谱模型,得到了光强闪烁激光雷达探测路径上闪烁指数与大气折射率结构常数之间的关系。分析了不同内尺度下大气湍流强度的变化情况,并与不考虑内尺度的情况进行了比较。结合实验数据对比分析了内尺度对光强闪烁激光雷达在探测大气湍流时的影响程度,结果表明在内尺度的取值变化范围内,采用修正Hill谱时,理论上有限内尺度的折射率结构常数与不考虑内尺度时折射率结构常数的比值可达9,实验中传输距离为1020 m和2040 m的传输路径上两者最大偏差为0.4和0.1个量级;Rytov改进模型下,理论上有限内尺度的折射率结构常数与不考虑内尺度时折射率结构常数的比值可达6,实验中同样传输路径上两者最大偏差为0.6和0.3个量级。理论和实验结果表明:有限内尺度的折射率结构常数测量结果在一定程度上偏离不考虑内尺度的折射率结构常数,且影响程度与激光传输距离和内尺度的大小有关。因此,在光强闪烁激光雷达的大气湍流探测过程中,必须考虑内尺度效应。

By using three atmospheric turbulence power spectrum models, namely Kolmogorov spectrum、 modified Hill spectrum and improved Rytov model, we obtain the relationship between scintillation index and atmospheric refractive index structure constant on detection path of residual turbulent scintillation lidar. Changes of turbulence intensity under difference inner scales are analyzed and compared with the situation that not considering the inner scale. The influence of inner scale on the detection of turbulence by residual turbulent scintillation lidar is analyzed according to experimental data. The results show that, in the range of inner scale, by using the modified Hill spectrum, the ratio of refractive index structure constant of the infinite inner scale to refractive index structure constant of not considering the inner scale is 9 in theory, and deviations are 0.4/0.1 orders in experiment at propagation distance of 1020 m and 2040 m, respectively. When we use the improved Rytov model, the ratio of refractive index structure constant of the infinite inner scale to refractive index structure constant of not considering the inner scale is 6, and deviations are 0.6/0.3 orders in experiment at propagation distance of 1024 m and 2040 m, respectively. Theoretical and experimental results show that, to some extent, the refractive index structure constant of the infinite inner scale is deviated from the situation of not considering the inner scale, which is related to propagation distance and the magnitude of inner scale. Therefore, inner scale must be considered in the detection of residual turbulent scintillation lidar.