拉曼激光雷达探测低对流层大气二氧化碳分布

Measurement of CO_2 Concentration Profiles of Lower-Troposphere with Raman Lidar

介绍了中国科学院安徽光学精密机械研究所研制成功的我国第一台测量低对流层大气CO2时空分布的拉曼激光雷达系统,选用波长355nm的紫外激光作为光源,利用光子计数卡双通道采集大气中N2和CO2的拉曼后向散射信号。详细分析了拉曼激光雷达系统的定标方法,提出采用Li7500型H2O/CO2分析仪与拉曼激光雷达系统进行对比与标定,结果显示激光雷达与CO2分析仪数据变化趋势一致性较好,激光雷达具有很高的探测灵敏度与准确性,通过线性拟合水平方向标定误差小于0.2%,垂直方向小于1.4%。由标定关系反演出大气中CO2的时空分布,给出了合肥西郊低对流层大气CO2水平方向0～2.0km与垂直方向0～2.5km分布的典型测量结果。

A prototype of Raman lidar first developed by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, for monitoring lower-tropospheric CO2 profiles in China is introduced. An ultraviolet laser with wavelength at 355 nm is selected as light source and a photon-counting card is used to acquire atmospheric Nz and C02 Raman backscattering signals. Methods of the Raman lidar system calibration are analyzed in detail and Li7500 H2 O/ COz analyzer is employed to contrast with our lidar. The results show good agreement in the trend of changing and verifying high detection sensitivity and accuracy of the lidar system. By linear fitting, the calibration error is smaller than 0.2% and l. 5% in horizontal and vertical direction, respectively. Then profiles of atmospheric C02 can be calculated in accordance with calibration equations and typical measurement results in the western suburbs of Hefei are given. The detection range can reach 2.0 km and 2.5 km in horizontal and vertical direction, respectively.