Retrieval of 13CH4 atmospheric content and CH4 isotopologues ratio from ground-based measurements of solar spectra

Abstract

Atmospheric monitoring of methane shows that CH 4 concentration growth since 2007 is accompanied by C 13 /C 12 isotopic delta ratio shift to more negative values due to 13 CH 4 content depletion. In the work, the atmospheric total column amount and vertical profiles of 13 CH 4 and 12 CH 4 are retrieved from the ground-based measurements of solar spectra in Kourovka observatory. The CH 4 isotopologues ratio is calculated. The error of the isotopologues content retrieval is estimated for different spectral regions. On basis of the obtained results, optimal spectral windows were found.