利用小波变换消除颗粒物Mie散射对DOAS技术的影响

为消除烟气中颗粒物Mie散射对差分吸收光谱(DOAS)法反演气体浓度的影响,提出了多项式结合小波变换的滤波方法.数值研究结果表明:对不同的颗粒物浓度和不同的气体浓度,采用该滤波方法都能够大幅度降低气体浓度的反演误差,且小波变换的层数随颗粒物浓度的增加而增加.实验研究表明:基于该滤波方法的DOAS技术,对0~1377.2mg/m3范围内的SO2气体,其浓度反演误差大都在10%以内,零点漂移由50.96mg/m3降为9.96mg,/m3,提高了DOAS技术的测量精度.

Eliminating Mie scattering influence of particles on DOAS technique using wavelet transform

A new filtering method of polynomial combining with wavelet transform is introduced in order to eliminate the influence of Mie scattering of particles on differential optical absorption spectroscopy(DOAS).Numerical research results show that for different concentrations of dust particles and gases,the DOAS based on the filtering method can be used to realize the accurate measurement of gas concentration.Also,it is advised that the layers of wavelet transform should be increased with the increasing concentration of dust particles.Experimental research results show that the error of SO2 inversion is less than 10% with the concentration range of 0 to 1377.2mg/m3 by applying the DOAS technique based on the filtering method.Zero drift of the improved DOAS system is reduced to 9.96mg/m3from 50.96mg/m3 and therefore,the accuracy of the system is greatly improved.