Study on temperature dependence of the greenhouse gases and carbon isotope ratio spectral analysis

To study the influence of temperature change on the spectrum quantitative analysis of greenhouse gases and carbon isotope ratio,at first, the view that the quantitative analysis of greenhouse gases and 13CO2 value was mainly determined by the absorption coefficient was analyzed theoretically, and the calculation method of the absorption coefficient was also studied. Then referring to the HITRAN database, the temperature dependence of line intensity, FWHM and absorption coefficient were studied, the results show that the effect of line intensity is stronger than the FWHM on the absorption coefficient when the pressure is constant at 1 atm while the temperature changes. At last, the temperature dependence of greenhouse gases and carbon isotope ratio quantitative analysis based on Fourier transform infrared spectroscopy(FTIR) method was confirmed through a series of experiment, and these experiments also present that the variation of carbon isotope is more serious than the greenhouse gases variation when the temperature changes, the 13CO2 value will change 14.37 while the temperature changes 1 ℃. This study is the theoretical basis for the design of the temperature monitoring and controlling system of greenhouse gases and carbon isotope ration monitoring instrument based on FTIR with high-precision.