Verification of the Radiometric Calibration of SCIAMACHY for two Alternative Key Data Sets: Comparison with MERIS Data

New key data (IfE NASA sphere and Spectralon + the corresponding patched-SRON files, October 2004) have recently become available. Here it is presented a comparison of their effects on the SCIAMACHY reflectance with respect to the MERIS reflectance between 442‐885nm. It is also presented a full spectrum for the Sahara desert as a function of the different key data versions. The new key data improves the reflectance offset. There is also a significant improvement in the solar irradiance radiometric calibration. However, new spectral features can be found. Eventually, the patched (SRON) and non-patched files show essentially the same behavior. Hence, there is strong evidence that the changes introduced by the new key data are mostly due to the improvement of the solar irradiance product.