The retrieval of stratospheric aerosol extinction profiles from limb scatter measurements

This paper is devoted to retrieve the stratospheric aerosol extinction profiles from the limb measurememts performed by Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instrument on the European Environmental Satellite. The SCIATRAN radiative transfer model is employed to simulate the limb radiance received by the SCIAMACHY instrument, and an optimal estimation method is used to retrieve the aerosol extinction profiles. For this retrieval, the measurement vector is defined as the ratio of two normalized spectral channels in order to minimize the effects of the uncertainty parameters and to reduce the impact of instrument calibration errors. The retrieved aerosol extinction profiles are compared with the Stratospheric Aerosol and Gas Experiment (SAGE) II measurements, and the results show that for the zonal mean profiles, SCIAMACHY retrievals exhibit good agreement with SAGE II measurements, with the relative differences being generally within 20% over the altitude range of 12-28 km.