拉曼散射激光雷达反演二氧化碳测量结果的可靠性分析

Reliability analysis of Raman scattering lidar for measurement of atmospheric carbon dioxide profiles

拉曼散射法测量大气二氧化碳(CO2)是一种利用大气中CO2分子和N2分子与激光相互作用产生Raman散射频移来实现探测CO2混合比分布的探测技术。介绍了中国科学院安徽光学精密机械研究所自主研制的拉曼散射激光雷达系统,以及用于大气CO2时空间分布测量的原理和方法。将两台事先校准过的CO2分析仪布置在激光雷达水平光路的发射端和1km位置进行同时测量,实验结果表明:两台分析仪分别与激光雷达近端和远端得到的CO2混合比随时间的变化具有较好的一致性,统计一整夜测量结果的平均值分别相差0.8ppm和3.51ppm;结合激光光路下垫面的不同对近端与远端结果的差异进行了分析说明,充分表明了拉曼散射激光雷达测量结果的可靠性。

Raman scattering lidar is an important technique, which has the high space-time resolution, can measure atmospheric carbon dioxide mixture ratio profiles in real time. It is based on the Raman scattering frequency shift caused by laser and atmospheric CO2 or N2 interaction. A Raman scattering lidar system developed by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, was introduced. And the theory and method for atmospheric CO2 space-time measurement were expatiated on. Two CO2 analyzers prior calibrated by each other, which tested the lidar′s results reliability, were placed in the sites of transmitting terminal and one kilometer distance along the laser path. Experiment results displayed the two analyzers have good consistency with the lidar′s in near-end and far-end respectively, where there are 0.8 ppm and 3.51 ppm difference in whole night averaged values. It was explained that the difference of CO2 mixture ratio in near-end and far-end. Thus atmospheric CO2 profiles monitored by Raman scattering lidar have authenticity and reliability.