Improved analysis of atmospheric absorption spectra by including the temperature dependence of NO2

Absorption spectra of NO2 measured at several temperatures between room temperature and 197 K are used to improve the analysis of zenith view, atmospheric absorption data in the 405-430 nm spectral range. The size of persistent features in the residual spectrum of the analysis is reduced by up to 50%, which in principle facilitates measurement of weakly absorbing species, such as OClO and IO. Details of the reduction algorithm are discussed.