为了研究差分吸收激光雷达低空CO₂浓度探测效率，分析了探测系统的原理与信噪比，采用近红外微脉冲激光雷达进行了仿真实验，当激光脉冲能量为20μJ、重复频率为10kHz时，推算出信噪比、所需积累时间与探测距离的关系。在不考虑背景噪声情况下(夜间工作)，可进行4．5km以下CO₂气体浓度的探测；考虑背景噪声情况下(白天工作)，只能探测2．4km以下的CO₂气体浓度。结果表明，选择夜间探测和更好的探测器件可以提高探测距离。

In order to study the efficiency of detecting thickness of CO₂ in low space by differential absorption lidar(DIAL),the detection principle and the SNR(signal to noise ratio)of the system were analyzed. With the simulation experiments of a kind of near-infrared micro pulse lidar with energy of 20μJ and repetition rate of lOkHz,the relation among the SNR,the needed accumulation time and detection distance was calculated. The results show that without regard to the background noise(working at night),the thickness of CO₂ can be detected below 4.5 km. Whereas,with regard to the background noise(working in daylight),the thickness of CO₂ can only be detected below 2.4km. The conclusion is drawn that working at night and with other better performance instruments can increase the detection distance.