SCIAMACHY Long-Term Monitoring Results

The SCanning Imaging Absorption spectroMeter for Atmsopheric CHartographY (SCIAMACHY) is a contribution to the ESA 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 Earthsine radiance and solar irradiance spectra simultaneously from about 214 to 2380 nm in nadir, limb and occultation viewing geometry. To assure the high quality of the SCIAMACHY data products over the mission, a continuous monitoring of the SCIAMACHY functionality and performance is essential. For this purpose the SCIAMACHY mission planning concept includes dedicated calibration measurements on a daily, weekly and monthly time scale. These calibration measurements are regularly analysed; they comprise solar and lunar measurements as well as measurements using SCIAMACHY’s internal light sources (spectral and white lamp). In this paper recent results of the SCIAMACHY calibration and monitoring activities are presented showing that the SCIAMACHY instrument is radiometrically very stable over time and especially sensitive enough to detect variations in the solar activity on a sub-percent level.