Theoretical precisions for sciamachy limb retrieval Original Research Article

The UV-vis-NIR spectrometer SCIAMACHY on ESAʹs Envisat will measure the back-scattered solar radiation from the Earthʹs atmosphere in limb geometry. From these measurements atmospheric parameter profiles will be retrieved (T, p, trace gas abundances, and aerosol and cloud parameters). Theoretical precisions for retrievals from SCIAMACHYʹs limb measurements are calculated with a fully spherical radiative transfer model and a realistic instrument model. The retrievals can be performed for the atmospheric layers above the top of optically thick clouds. The vertical resolution of the retrieval parameter profiles is 3 km. O3 profiles can be measured with a theoretical precision of 1% throughout the stratosphere and in the upper troposphere. The retrievals of other trace gases (NO2, BrO, CH4, …) will have precisions between 2 and 100 % depending on retrieval altitude.