The SCIAMACHY calibration/monitoring concept and first results

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) is a contribution to the ENVISAT satellite, which has been launched successfully in March 2002. SCIAMACHY determines the amount and distributions of a large number of atmospheric constituents by measuring Earthshine radiance and solar irradiance spectra simultaneously from the UV to the NIR in various viewing geometries. The scientific goals of the SCIAMACHY mission can only be reached by an instrument having a high spectral and radiometric accuracy and stability. For example, to determine global NO2 concentrations SCIAMACHY measurements need to be sensitive to differential spectral structures down to the order of 10(-4). These requirements can only be met by an appropriate instrument design in combination with both on-ground and in-flight calibration and monitoring. This paper gives an overview on the SCIAMACHY calibration and monitoring concept and activities which are essential to ensure the high quality of SCIAMACHY data products throughout the instrument lifetime. Furthermore, first in-flight monitoring results are presented. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.