基于法布里-珀罗干涉仪的瑞利-米散射测风激光雷达研究

Rayleigh-Mie Wind Lidar Based on Fabry-Perot Interferometer

为了研制探测中高层风场的瑞利-米散射多普勒激光雷达系统,前期在实验室搭建了一套基于三通道法布里-珀罗干涉仪(FPI)的532 nm瑞利-米多普勒激光雷达验证系统,并进行实际比对实验。利用验证系统,首先开展了FPI透过率校准实验,采用非线性拟合方法获得了三个通道FPI实际透过率曲线,FPI-1、FPI-2和FPI-L的谱宽分别为1.20 GHz、1.22 GHz、1.18 GHz,峰值透过率分别为0.817、0.807、0.768,FPI-1和FPI-2及FPI-1和FPI-L的峰峰间隔分别为3.91 GHz和1.25 GHz,并进一步给出了米散射和瑞利散射信号入射时系统实际的风速探测灵敏度。其次,开展了径向风速连续观测实验和水平风场对比观测实验。实验结果表明:在单次径向风速测量中,时空分辨率为2 min和75 m的情况下,系统白天和晚间分别具备10 km和16 km左右高度的风场探测能力。在白天2.7~10 km、晚间1.5~10 km高度范围内,系统测得的水平风场数据与探空气球测得的水平风场数据吻合度较高,晚间70.8%的水平风速和风向数据偏差小于2 m/s和10°;95%的水平风速和风向数据偏差小于5 m/s和15°,充分验证了系统风场测量结果的准确性。

In order to develop a Rayleigh-Mie Doppler lidar system for detecting mid-to-high wind fields, a set of 532 nm Rayleigh-Mie Doppler lidar verification system based on triple Fabry-Perot interferometer(FPI) was previously built and the actual comparison test was conducted. Using the verification system, the FPI transmission calibration experiment was carried out firstly, and the actual transmission curves of triple FPI were obtained by using the nonlinear fitting method. The spectral width of FPI-1, FPI-2, and FPI-L were 1.20 GHz, 1.22 GHz, and 1.18 GHz respectively, the peak transmission were 0.817, 0.807, and 0.768 respectively, and the peak intervals of FPI-1 & FPI-2 and FPI-1 & FPI-L were 3.91 GHz and 1.25 GHz respectively. Furthermore, the actual wind speed detection sensitivity of the system was given when both of the Mie and Rayleigh scattering signals were incident. Secondly, continuous observation experiment of radial wind speed and comparative observation experiment of horizontal wind field were carried out. The experimental results show that in the single radial wind speed measurement, the system has the capable of detecting wind field at a height of about 10 km and 16 km in the daytime and night respectively with the time resolution of 2 min and spatial resolution of 75 m. In the height range of 2.7 km to 10 km in the daytime and 1.5 km to 10 km in the night, the data of the horizontal wind field measured by the verification system coincide with those measured by the balloon. In the night, 70.8% of the horizontal wind speed and direction data deviation is less than 2 m/s and 10°, and 95% of the data deviation is less than 5 m/s and 15°, which fully verifies the accuracy of the system wind field measurement results.