温室气体及碳同位素比值红外光谱反演精度的影响因素研究

Influence factors of quantitative analysis precision of greenhouse gases and carbon isotope ratio based on infrared spectroscopy

由于傅里叶变换红外光谱(FTIR)技术在定量反演中受到气体温度、压强等气体特性以及水汽交叉吸收的影响,使其在温室气体及碳同位素比值高精度检测领域的应用受到限制.本文首先研究了气体特性与水汽吸收敏感性修正方法;然后,结合实验研究中建立的敏感性修正函数,对标准气体实测数据进行了气体特性敏感性修正,修正后,五种测量组分的精密度均有明显提高,其标准偏差降低倍数分布在1.80到3.38之间.研究结果对于FTIR技术在大气本底温室气体及碳同位素比值高精度监测领域的应用具有重要意义.

The quantitative analysis based on Fourier transform infrared （FTIR） technology is affected by the temperature and pressure properties of gas and the H2O cross section, so the applications of FTIR technology to high-precision measurement area of the greenhouse gases and isotope ratio are restricted. Firstly, the methods of correcting the gas property sensitivities and H2O cross sensitivity are studied, then the standard gas measurements are corrected with these sensitivity correcting functions established through experimental study. The standard deviations of CO, CO2, N2O, CH4 andδ13CO2 are all improved after correcting the sensitivities, and reduced by 1.80–3.38 times. These studies are significant for the applications of FTIR technology to the high-precision measurement area of greenhouse gases and isotope ratio.