Evaluation of the combined differential-integral approach for limb viewing geometry Original Research Article

A new Combined Differential-Integral (CDI) radiative transfer model was recently developed to perform fast and accurate computations of the scattered solar radiation at the top of the atmosphere for non-limb viewing geometries. The new model requires significantly less computer time than a fully spherical model and is more accurate for off-nadir viewing geometries than commonly used pseudo-spherical models. In this paper the accuracy of the simulation of the differential optical depth spectra in limb viewing geometry using the CDI radiative transfer model is investigated. The CDI model is found to be suitable to perform forward calculations for ozone and NO2 vertical profile retrieval using the differential approach.