The effect of photochemically active species and clouds on the relationship between radiance and concentration profiles

The use of radiance measured by satellite sensors to estimate the concentration of chemical species in the atmosphere depends upon the correlation between measured radiances and atmospheric concentration profiles. The relationship is examined for a specific problem, namely the retrieval of the distribution of members of the nitrogen oxides family from satellite sensors solar occultation measurements at time periods of high photochemical activity, at the presence of clouds and for the lower stratosphere. It is found that the nitric oxide relationship depends strongly on both the presence of clouds and on the temporal and spatial variation of NO and nitrogen dioxide, whereas for the NO2 relationship the dependence is weaker and is also influenced by the limitations of the applied inversion algorithm.