反演波段对DOAS测量大气中O_3的性能影响研究

The Effect of Spectral Range on the Measurement of Ozone in the Atmosphere by DOAS

臭氧(O3)浓度通常被认为是一个地方污染水平的基准,所以其绝对值的准确性至关重要。在差分光学吸收光谱技术(DOAS)对O3的测量过程中,光谱反演波段的选择可直接决定O3浓度的测量准确度。文章主要研究了在不同光谱波段O3特征吸收结构和差分光学厚度(D′)的不同,在不同光谱波段O3浓度反演的干扰来源以及影响程度,确定了实际检测时大气消光对不同波段光强的影响,最后通过对多种污染物标准气体进行了同时监测,计算出标准气体在不同光谱分辨率不同O3浓度时的测量误差,确定了对O3的最适用光谱波段范围。在此波段既能够实现对痕量气体的准确定性定量,又能达到测量所需要的高灵敏度,强选择性和适用的时间分辨率。

Ozone （O3） often serves as the benchmark for the overall pollution level of a given airshed and it is critical that the measurement technique be accurate and precise. In the DOAS measurement, the accuracy of O3 concentration is determined by the selected spectral range. The present paper focuses on the effect of spectral range on the detected characteristic absorption structure of O3, and the variation of differential cross section of O3 with the change in spectral range and the source of interference in different spectral range. The effect of practical atmospheric light extinction on the light intensities of different spectral ranges was deduced; the effect of spectral range on the accuracy was determined by detecting the standard gases at different concentration and different spectral resolution. The optimized spectral range was determined for O3, which can yield high sensitivity, good selectivity and a reasonable time resolution for the accurate qualitative and quantitative analysis of O3.