935nm大气水汽探测差分吸收激光雷达技术研究

发布时间：2018-07-10 20:23

本文选题：激光雷达 + 差分吸收　；参考：《中国科学院研究生院(上海技术物理研究所)》2016年博士论文

【摘要】：水汽是地球大气层中唯一存在相变的物质,在许多大气物理与化学过程中都起到很重要的作用;在对流层,水汽影响气溶胶和云层的形成,而且其浓度及分布随地域、季节、昼夜、海拔高度的变化很大,对气象和气候会产生重大影响。因此,得到高精度、高时空分辨率的水汽浓度廓线数据对于气象和气候研究有非常大的帮助,采用差分吸收激光雷达作为探测设备是一种非常好的选择。针对大气水汽探测差分吸收激光雷达技术开展了关键技术研究,并研制了一套基于935nm波段的实验系统,为其以后的工程应用奠定了基础。首先进行了详细的理论推导,分析了引起浓度测量误差的各因素及误差的计算方法;结合上海地区的气候,对935nm附近三个吸收峰在夏季和冬季的探测性能进行了仿真,结果表明波长为935.906nm的吸收峰适合于夏季探测,波长为935.776nm的吸收峰适合于冬季探测。然后设计了一套基于935nm的地基实验系统,分析了系统各部分的工作原理与性能参数,研制了其关键部件并进行了性能测试实验;并提出了一种脉冲间隔扫描式激光频率稳定方法,实验表明其稳频精度30MHz,可以满足本系统的需求。接着讨论了雷达回波信号的处理算法,并开发了基于Lab VIEW的处理软件,可以实时反演出水汽浓度廓线并存储实验数据。实验获得了上海地区对流边界层的水汽浓度廓线数据,在时间分辨率为60s,距离分辨率为30m时,白天和夜晚在高度600m至对流边界层顶的范围内随机测量误差均小于0.1g/m3,与附近气象观测站无线电探空仪数据的对比结果证明了雷达数据的有效性。
[Abstract]:Water vapor is the only material in the earth's atmosphere that has phase transitions and plays an important role in many atmospheric physical and chemical processes. In the troposphere, water vapor affects the formation of aerosols and clouds, and its concentration and distribution vary with the region, season, and season. Day and night, altitude changes a lot, will have a major impact on meteorology and climate. Therefore, it is very helpful for meteorological and climate research to obtain high accuracy and high spatial and temporal resolution water vapor profile data. It is a good choice to use differential absorption lidar as detection equipment. The key technology of differential absorption lidar for atmospheric water vapor detection is studied, and a set of experimental system based on 935nm band is developed, which lays a foundation for its future engineering application. Firstly, the detailed theoretical derivation is carried out, the factors causing the error of concentration measurement and the calculation method of the error are analyzed, and the detection performance of the three absorption peaks near 935nm in summer and winter are simulated according to the climate in Shanghai. The results show that the absorption peak with 935.906nm wavelength is suitable for summer detection and the absorption peak with 935.776nm wavelength is suitable for winter detection. Then, a foundation experiment system based on 935nm is designed, the working principle and performance parameters of each part of the system are analyzed, the key parts are developed and the performance test experiment is carried out. A pulse interval scanning laser frequency stabilization method is proposed. The experimental results show that the frequency stabilization accuracy is 30 MHz, which can meet the needs of the system. Then, the processing algorithm of radar echo signal is discussed, and the processing software based on LabVIEW is developed, which can invert the water vapor profile and store the experimental data in real time. The data of water vapor concentration profile in the convective boundary layer of Shanghai area are obtained experimentally. When the time resolution is 60 s and the distance resolution is 30 m, The random measurement error is less than 0.1 g / m ~ 3 between day and night in the range from 600 m to the top of the convective boundary layer. The comparison with the radiosonde data of the nearby meteorological observation station proves the validity of the radar data.
【学位授予单位】：中国科学院研究生院(上海技术物理研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN958.98

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