基于碘分子滤波器的高光谱分辨率激光雷达原理

Theory of Iodine Filter Based on High Spectral Resolution Lidar

碘分子1107～1108吸收线之间有一个光谱透射率峰。基于该光谱透射率峰的碘分子滤波器对大气分子的瑞利散射有强烈的抑制作用,而对大气气溶胶的Mie散射影响较小。利用这种碘分子滤波器构成的高光谱分辨率激光雷达可以分离大气分子散射和气溶胶散射,从而能够测量大气后向散射比和大气风场。对测量原理和测量精度进行了详细推导,并利用合理的激光雷达和大气参数进行了计算机模拟。模拟结果表明,对于大气后向散射比的测量,夜晚大气高度25km、白天8km以下可以达到5%的精度;大气视线风速测量范围为±40m/s,测量精度在夜晚大气高度5km、白天4km以下时优于5%。

There is a spectral transmission peak between 1107 and 1108 absorption lines of iodine.The spectral transmission peak can suppress the atmospheric Rayleigh backscattering,while affect weakly on the atmospheric Mie backscattering.The high spectral resolution lidar,in which the above iodine filter acts as the ultra-narrow band filter to the Rayleigh and Mie backscattering signals,can measure the atmospheric backscattering ratio and wind field.The measurement theory is deduced and simulated by using reasonable lidar parameters and atmospheric models.The simulation results show that for the atmospheric backscattering ratio measurement,the precision is 5% for altitude lower than 25 km at night and 8 km in daytime.For the line-of-sight wind velocity measurement,the measuring range is ±40 m/s and the precision is 5% for altitude lower than 5 km at night and 4 km in daytime.