Retrieval of column-averaged volume mixing ratio of CO2 with ground-based high spectral resolution solar absorption

Abstract

The total column-averaged volume mixing ratio of atmospheric carbon dioxide (\( {\text{X}}_{{{\text{CO}}_{ 2} }} \)) has been retrieved with high spectral resolution solar absorption data obtained from ground-based Fourier transform spectrometer (FTS) measurements at Xichong, a coastal site in the district of Shenzhen in southern China. Based on differential optical absorption spectroscopy (DOAS) theory, the \( {\text{X}}_{{{\text{CO}}_{ 2} }} \) was retrieved by finding the best match of observed high spectral resolution solar absorption data and monochromatic radiation transfer model calculations. The averaged \( {\text{X}}_{{{\text{CO}}_{ 2} }} \) in the whole observation period was about 394.9 ppm. The uncertainty of the retrieval was estimated to be 2.0 ppm (0.51 %) by comparing retrievals at two bands. The preliminary results show that \( {\text{X}}_{{{\text{CO}}_{ 2} }} \) retrieved by this method can be used to validate satellite remote sensing of \( {\text{X}}_{{{\text{CO}}_{ 2} }} .\)