Radiative transfer model MCC++ with evaluation of weighting functions in spherical atmosphere for use in retrieval algorithms Original Research Article

A linearized radiative transfer model MCC++ designed for use in retrieval algorithms was developed. It calculates the weighting functions with respect to the absorption in all atmospheric layers and the layer air mass factors simultaneously with the intensities. Multiple scattering radiance is calculated by the Monte Carlo methods for spherical atmosphere taking into account the polarization of light, aerosol loading of atmosphere and the Lambertian surface albedo. A validation of the MCC++ model against other radiative transfer models is presented. It includes a comparison of weighting function calculations, a comparison for the scattering limb geometry, a comparison for twilight ground-based observations. As an example, additional errors of Brewer Umkehr retrieval algorithms, when they use the weighting functions calculated for approximation of single-scattering, are evaluated.