Influence of prior profile on retrieval of greenhouse gas CO2 concentration from ground-based infrared remote sensing

Abstract

The increase of greenhouse gas concentration is the most important factor leading to global warming, and the accuracy of carbon dioxide column concentration is required to be better than 0.25% in the total carbon column observation network. As the prior value of inversion model, the influence of prior profile on inversion accuracy needs to be further clarified. Based on Observation of the column-averaged dry air mole fractions of carbon dioxide in Hefei, the sensitivity of temperature profile, pressure profile and CO₂ molecular profile to the column-averaged dry air mole fractions retrieval was analyzed. The main results are as follows: The temperature and pressure profiles have significant influence on the inversion results, the relative deviation of retrieving CO₂ column concentration from the temperature and pressure profiles of 1976 US standard atmosphere and NCEP is 3.8%, and the maximum absolute deviation between them is 14ppm; The shift of the prior CO₂ profile has no effect on the inversion accuracy. However, the change of the profile shape has a significant effect on the inversion accuracy. Therefore, using real-time temperature and pressure profiles and accurate gas prior profiles can improve the retrieval accuracy of greenhouse gas CO₂ column concentration. These results provide a theoretical basis for the inversion of greenhouse gas column concentration in China.