本文探讨在背景噪音影响下,差分吸收激光雷达测量臭氧的不确定性:背景噪音对臭氧浓度廓线的影响正比于背景噪音强度、强吸收波长和弱吸收波长的回波信号强度比.理论计算结果表明：合适的回波信号强度比可以使激光雷达背景信号对夜间臭氧探测浓度的影响变得非常小,可以忽略不计.实验结果表明：用波长对（280 nm,285 nm）对大气臭氧进行观测时,适当调节两波长回波信号强度比为0.96时, 背景信号对臭氧浓度探测的影响小到可以忽略的程度.模拟分析和实验观测结果相接近，证实了理论推算的合理性.在背景噪音强度未知的情况下，通过调整强吸收和弱吸收两波长的激光脉冲的能量，在示波器上得到适合的回波信号强度比值，可以抑制背景噪音信号对臭氧探测结果的影响，确保夜间臭氧测量的准确性.

The uncertainty of ozone differential absorption lidar (DIAL) measurements due to the effect of background noise is presented. The effect of background noise on ozone concentration profiles is proportional to the background intensity and the ratio of return signal intensities at “on” and “off” wavelength. Analysis suggests that an appropriate return signal intensity ratio can make the effect of background signal very small, negligible. The simulations based on the analysis coincide with the experimental results.The experimental results show that the impact of background signal is negligible at an appropriate return signal intensity ratio of 0.96 at wavelength pair (280 nm,285 nm). In case of unknown background intensity, we can adjust the laser pulse energy levels at the two wavelengths to obtain an appropriate return signal intensity ratio on the oscilloscope to suppress the impact of background signal and ensure the accuracy of night time ozone measurements.