将差分吸收光谱法（DOAS）应用于NH3浓度反演。在传统的DOAS算法基础上，研究遗传算法、小波变换和卡尔曼滤波三种算法对低浓度NH3反演精度的影响。研究结果表明，对于信噪比较低的NH3吸收光谱信号，三种算法都具有良好的去噪能力。在NH3浓度低于7.6 mg/m3的情况下，三种算法的反演精度相对于传统的DOAS算法明显提高。其中传统的多项式滤波法结合卡尔曼滤波法差分吸光度残差标准差为0.1341%，峰峰值为0.6132%，反演精度最高，误差在±0.3%以内。

The method of differential optical absorption spectroscopy (DOAS) is applied to the retrieval of ammonia concentration. Genetic algorithm, wavelet transform and Kalman filtering are all studied to show the inversion accuracy of low-concentration ammonia based on the traditional DOAS algorithm. The results show that all the three algorithms have good denoise performance for ammonia absorption spectrum with low SNR. In the case of ammonia concentration lower than 7.6 mg/m3, the inversion accuracy for three improved algorithms is obviously improved compared with the traditional algorithm. Standard deviation and peak to peak value of the differential absorbance residuals based on Kalman filtering combining traditional polynomial fitting are 0.1349% and 0.6132%, respectively, which shows the best performace. The measurement error is within ±0.3%.