应用二维相关提高DOAS技术的温度鲁棒性

Improving the Temperature Robustness of the DOAS Based on Two-Dimensional Correlation Spectroscopy Technology

利用差分光学吸收光谱(DOAS)技术对空气中污染气体的浓度进行实时监测时,测量结果的准确度会受到环境温度变化的影响。为此,提出了通过二维相关光谱技术优选波长来提高DOAS测量中温度鲁棒性的方法。通过对不同温度下SO2的吸收截面进行二维相关分析,得到了动态吸收截面同步相关谱对角线的自助峰,据此分析了不同波长下吸收截面随温度变化的敏感程度,进而优选出最佳反演波长范围300.5～310nm。在将波长优选前后现场的测量结果和参考值进行对比时显示:采用优选波长前后24h的平均测量误差由22.5%减小至9.9%,测量值和参考值的相关系数由0.780 8提高到了0.949 6。结果表明,二维相关光谱和DOAS技术相结合,可以准确测量污染气体浓度。

The accuracy of the measurement results will be influenced by the ambient temperature in the real-time monitoring based on Differential Optical Absorption Spectroscopy（DOAS）.A novel method to improve the temperature robustness of DOAS technology is adopted by two-dimensional correlation spectroscopy technology.Two-dimensional correlation is used to analyse the SO2absorption cross section at different temperatures.The diagonal slices of synchronization correlation spectroscopy which come from dynamic absorption cross section are obtained.The wavelength 300.5～310nm is used as the preferred inversion wavelength range based on the slices.The field measurement results and reference value are compared.Results show that the 24-hour average measurement error is 22.5%at 290～310nm and that at 300.5～310nm is 9.9%.The correlation coefficients are 0.949 6and 0.780 8,respectively.Two-dimensional correlation DOAS technology can be applied to enhance the robustness of temperature,and to improve the accuracy of the measurement results.