有机气溶胶的微脉冲荧光激光雷达水平近场探测研究

Horizontal near-field detection of organic aerosols by micro-pulse fluorescence lidar

微脉冲激光雷达技术是大气气溶胶观测的重要手段,当使用紫外激光光源时,可利用激光诱导荧光信号探测环境中的有机气溶胶。建立了微脉冲荧光激光雷达水平探测有机气溶胶的仿真模型,并对回波光子数及信噪比进行了数值仿真计算。根据仿真结果设计并搭建了一台微脉冲荧光激光雷达,通过对系统进行几何重叠因子标定,减小了近场荧光回波信号的强度误差。以营养肉汤溶液为气溶胶样本对该激光雷达系统开展了测试实验,实验表明该MPFL系统空间分辨率为7.5m,实验最大探测距离达到200m。同时与另一台低重频高脉冲能量的荧光激光雷达进行了对比实验,对比结果显示,两型激光雷达接收的荧光信号强度变化趋势具有很好的一致性,相关系数达82%以上。在相同的累加时间下,MPFL荧光信号变化率矩阵标准误差小于0.02%,具有更好的抗干扰性能,能够实现对有机气溶胶准确探测,验证了系统有效性和实用性。

Micro-pulse Lidar(MPL)technology is an important means of atmospheric aerosol observation,laser-induced fluorescence signals can be used to detect organic aerosols in the environment when using ultraviolet laser light sources.A simulation model for the horizontal detection of organic aerosols by micro-pulse fluorescence lidar(MPFL)is established,and the number of echo photons and signal-to-noise ratio are numerically calculated.According to the simulation results,a micro-pulse fluorescence lidar was designed and built,and the intensity error of the near-field fluorescence echo signal was reduced by calibrating the geometric overlap factor of the system.The test experiment of the lidar system was carried out using the nutritional broth solution as the aerosol sample,and the experiments showed that the spatial resolution of the MPFL system was 7.5m,and the maximum detection distance of the experiment reached 200m.At the same time,a comparative experiment was carried out with another fluorescence lidar with low repetition frequency and high pulse energy,and the comparison results showed that the trend of fluorescence signal intensity received by the two types of lidar had good consistency,and the correlation coefficient was more than 82%.Under the same accumulation time,the standard error of the MPFL fluorescence signal change rate matrix was less than O.02%,which had better antiinterference performance,and could achieve accurate detection of organic aerosols,which verified the effectiveness and practicality of the system.