差分吸收光谱技术测量氯气的数据处理方法研究

基于差分吸收光谱(DOAS)技术，结合自主搭建的一套小型便携式DOAS实验系统，开展了对氯气的实验测量。在处理氯气的标准截面时，比较了两种不同的高通数字滤波方法：三角函数滤波和多项式拟合滤波。实验证明采用后一处理方法能够更加准确反演出氯气的浓度。模拟计算的结果显示，采用五阶多项式处理的结果的误差较小;在不同样品池内的测量结果显示，利用该方法测量氯气的线性度达到0.996 1;实际的一条谱的反演结果显示拟合谱与测量谱基本重合，且剩余噪声谱的峰峰值最大值<5‰;给出整个实验过程中可能的误差主要来源。综合以上的实验结果表明，利用DOAS技术采用多项式拟合处理的方法可以实现对于氯气的检测。

Studies on the Data Processing Method in Chlorine Measurement by Differential Optical Absorption Spectroscopy Technology

In this paper,based on Differential Optical Absorption Spectroscopy(DOAS) technique,experimental measurements of chlorine was carried out in the laboratory with a small self-built experimental system.In dealing with the standard cross-section of chlorine,we presented two different methods: triangle filtering and polynomial fitting.Experiments showed that the concentration of chlorine could be accurately retrieved by the latter one.Simulation results showed that the error of retrieval result by fifth-order polynomial fitting was smaller than by other orders and an actual retrieval example shows that the fitting spectrums were nearly coincident with the measured spectrums with a residual delta(peak to peak) below 5‰;The results measured in different sample pools displayed a high linearity of 0.996 1 by this method.The main sources of errors during the entire experiment were simply analyzed.According to the experimental result above,it is feasible to detect chlorine using DOAS technology by polynomial fitting.