Development of a scanning lidar system for measuring the distribution of urban air pollution

我们开发了一种紧凑的扫描差分吸收激光雷达（DIAL），用于测量空气污染气体（臭氧，二氧化氮，二氧化硫）浓度的空间分布。本研究的最终目的是观察这些空气污染气体浓度的空间分布，特别是在城市地区，明确污染的结构和扩散情况。我们将提供的结果总结如下：(1)研制了激光系统，该系统产生的紫外线辐射用于二氧化硫和臭氧的测量。激光系统由Nd:YAG激光泵浦染料激光器和二次谐波产生光学晶体组成。这种激光系统比染料激光更容易维护和处理。我们成功地用波长计和标准子测量了波长和谱线宽度。(3)对于扫描激光束和视场的方法，我们采用了反射镜的方法，然后设计并制作了扫描系统。(4)对差分吸收激光雷达的测量精度和最合适的波长组合进行了计算机模拟。(5)通过计算机仿真建立了扫描激光雷达的处理算法。

We have developed a compact scanning difference absorption lidar (DIAL), which measured spatial distribution of the air pollution gas (ozone, nitrogen dioxide, sulphur dioxide) concentration. Final goal of this study is to observe spatial distribution of these air pollution gas concentrations particularly in urban area and clarified the structure and the diffusion situation of contamination. We summarize provided result as follows ; (1)We developed the laser system, which generated ultraviolet radiation for the sulphur dioxide (SO2) and the ozone measurement. The laser system consists of the Nd:YAG laser pumped dye laser and an optical crystal for second harmonic generation. This laser system is easier than the dye laser to maintain and handle. We succeeded in measurement of wavelength and spectral linewidth using a wavemeter and etalon. (3)For the method of scanning a laser beam and a field of view, we adopted the mirror method then we designed and produced the scanning system. (4)We did computer simulation about accuracy of measurement of a differential absorption lidar and the most suitable wavelength combination. (5)We established processing algorithm of a scanning lidar by computer simulations.