利用改进的瑞利测风激光雷达进行70km高度大气风场观测

Doppler lidar would be able to provide the most important wind field parameters for the mesosphere and lower thermosphere atmosphere science research and near-earth space flight. And it is a new and important detection means. This project is focusing on the research of the performance improving and efficiency promotion for Rayleigh Doppler wind lidar. And break through detection limit of 60km altitude and realize 70km altitude atmosphere wind field detection. the signal to noise ratio required is analyzed at 70km altitude for atmospheric wind field measurement, and coupling efficiency of optical signal, transmission efficiency of optical signal, collecting efficiency of optical signal are all improved for increasing optics efficiency of system and the signal to noise ratio, and compensating the declining of the signal to noise ratio because of increasing altitude and descending backscatter ratio. A new improved locking filter for a Fabry–Perot Interferometer was considered and designed with a high spectral resolution improve laser frequency locking accuracy based on the theory analysis. Zero wind velocity calibration procedure by the broaden laser pulse or backscatter signal from zero wind velocity layer in the atmosphere remove the measurement error because of Doppler zero deviation. Atmosphere wind field observation at 70km altitude is implemented based on the improved Rayleigh wind lidar. And lower stratosphere wind field is also measured by the lower stratosphere Doppler lidar. And high temporal and resolution wind profile data will be obtained in many areas for studying the changing discipline of mesosphere and lower thermosphere and understanding the region changing characteristic of space environment better, and providing necessary data support for space science research and near-earth space flight.

多普勒激光雷达能够为中高层大气科学研究和近地空间飞行提供关键的风场参数，是新的重要探测手段。本项目旨在开展瑞利测风激光雷达系统性能改进和效率提升研究，突破现有60km探测极限，在相同精度和时空分辨率下实现70km大气风场观测。分析70km高度大气风场探测所需的信噪比，通过改进接收系统光信号的耦合效率、传输效率和采集效率，有效提高系统的光学效率，提高信噪比，补偿由于探测高度增加和后向散射比降低所产生的信噪比下降。提出通过优化锁定通道透过率曲线光谱分辨率来改进激光频率漂移锁定精度的方法；增加零风速校准，消除由于多普勒零点偏移所产生的测量误差，进一步提高系统探测精度。利用改进的瑞利测风激光雷达进行70km大气风场探测实验，结合低平流层多普勒激光雷达系统获取多区域高时空分辨率的风廓线数据，为研究中高层大气变化规律、更好地认识空间环境的区域变化特征，为空间科学研究和近地空间飞行提供必要的数据支持。

大气风场的探测和研究是深入研究大气动力学、全球大气活动和空间环境预警的最主要参数之一，对行星尺度动力学、天气尺度动力学以及中小尺度天气系统动力学的研究具有重要的意义。多普勒激光雷达能够为中高层大气科学研究和近地空间飞行提供关键的风场参数，是新的重要探测手段。. 多普勒测风激光雷达可以有效解决我国中高层大气风场探测手段匮乏的问题，而高精度、高时空分辨率的大气风场连续测量需要具备光学效率高、结构紧凑、光路调节简单、校准程序稳定、可靠、精确的系统结构设计。本项目利用非偏振分光-反射棱镜组代替现有技术中的光纤分束器，解决了目前紫外波段光学效率低的问题；通过理论分析，提出了通过优化F-P标准透过率曲线光谱分辨率来提高激光频率漂移锁定精度的方法；利用激光脉冲展宽信号或零风层后向散射信号进行零风速校准，解决了多普勒零点偏移所产生的测量误差。通过现有瑞利测风激光雷达系统性能的改进和效率的提升研究，突破了现有60km探测极限，60km以上风速风向探测精度分别为10.3m/s和29度，符合探测指标要求，可以为临近空间大气动力学研究和气象观测提供必要的数据支持。利用改造后的激光雷达进行了区域分布式大气风场探测实验，获得了多区域高时空分辨率的风廓线数据，跟踪了大尺度季节性气候特征的变化规律，突出了小尺度瞬态气候特征的形成、演化过程。. 通过连续风场实验完成了我国西北地区某实验基地XXX项目中高层大气风场数据实时连续测量的保障任务，并获取了多区域高时空分辨率的风场数据，为研究中高层大气变化规律、认识空间环境的区域变化特征提供了必要的数据支持。该项目研究结果还为研究天气现象的形成机理、发生、发展及移动演变规律提供了重要的数据支撑，正确预测、预报了天气现场，为航天器的再入过程、回落点精度以及飞行器的安全等提高了必要的气象保障，同时也为导弹精确命中目标研究提供了必不可少的重要参数。