Spectroscopic measurements of O <sub>3</sub> and NO <sub>2</sub> atmospheric content: Improvements to ground-based method and comparison with the data of satellite observations
The results of daily observations of O <sub>3</sub> and NO <sub>2</sub> atmospheric total conent around St.Petersburg, retrieved from the automatic ground-based measurements of zenith-sky scattered visible solar radiation, are presented. The measurements acquired in 2009-2013 are compared with the data of satellite observations by the GOME (ERS-2), SCIAMACHY (ENVISAT) and OMI (AURA) instruments. Investigation of the disagreement revealed between the data of satellite and ground-based measurements allowed us to improve the ground-based method (DOAS technique) and reduce the average difference down to ~ 2 and ~ 20% for O <sub>3</sub> и NO <sub>2</sub> content, respectively. Remaining differences may be further reduced if the seasonal variability of calculated air mass factors is taken into account in the ground-based method.