- The background atmosphere is approximated using the ECMWF analysis for both presssure and temperature. The profiles are interpolated to the median location o fthe OSIRIS scan.
- The initial estmate of NO2 is derived from interpolation of the the Pratmo climatology.
- The initial aerosol estimate is a typical log normal sulphate profile provided by Deschler.
- The initial ozone is derived from an interpolation of the Labow climatology.