Sensitivity experiment of the DOAS retrieval of nitrogen dioxide based on SCIATRAN mode.

Aerosol and surface albedo are two important factors influencing quantitative remote sensing NO2 column with SCIAMACHY observed data. Using high resolution atmosphere radiation transfer model SCIATRAN as well as considering molecules absorption and aerosol multiple scattering, the effects of aerosol, surface albedo and NO 2 concentration changes on the satellite reflection spectrum before and after differential processing are accurately simulated, Influence factor f is defined, and the comprehensive evaluation of three simulation parameters performed. The results are: (1) DOAS method has obviously reduced the effect of aerosol and surface albedo on satellite reflection spectrum by eliminating slow changing part of spectrum; (2) Before differential processing, three simulated parameter's influence strength is successively surface albedo, aerosol and NO2 concentration; then after processing, the order is NO2 concentration, surface albedo and aerosol. The aerosol and surface albedo are very similar in the influence tendency, and both have a wide band effect. And the big peak value in 440-45 0 nm is caused by water vapor strong absorption and multiple scattering complex interaction. NO2 concentration change displays its intrinsic absorption structure impact on the satellite reflection spectra before and after processing; (3) Due to the effect of interactions of absorption, scattering and other factors, the differential spectrum based on satellite observed data still contain errors caused by aerosol (about 6.2%) and surface albedo (about 18.6%). Consequently，the current SCIAMACHY NO2 concentration over China is too higher, and needs to be sophistically corrected for aerosols and surface albedo.