连续波差分吸收激光雷达测量大气CO_2

研制了一套接收硬目标回波的差分吸收激光雷达系统以用于全天候监测大气CO2浓度变化.系统采用10和12 kHz正弦波分别对处在CO2吸收峰内和吸收峰外的波长进行强度调制,利用单频检测技术提取回波信号.提出了一种利用激光扫频推算系统精度的方法,从而弥补了长期以来只能在理论上计算差分吸收激光雷达系统精度的不足,给实际系统自定标问题提供了一种解决方案.该系统采用全光纤结构,结构可靠,便于移动.利用此系统获得了上海市多天CO2浓度变化曲线,在450 m的积分路径长度上,1 s的积分时间取得了优于3.39×10-6的测量精度.

Continuous-wave modulation differential absorption lidar system for CO2 measurement

An intensity modulation hard-target differential laser absorption lidar system for CO₂ sensing is demonstrated. On and off wavelength lasers are modulated with 10 kHz and 12 kHz sinusoidal waves. The echo is extracted using coherent detection technique. The system is fiber based, which makes it compact and removable. We obtain three day variation of horizontal column averaged CO₂ concentration of Shanghai district. We also propose an accuracy evaluation method based on electronic noise analysis combined with laser frequency modulation. The result shows that the measurement precision for the column corresponds to 3.39×10^-6 (rms) with 1s integral time and 450 m path.
Keywords： continuous-wave modulation differential absorption lidar 2')" href="#">CO₂ precision evaluation