SCIAMACHY Degradation Monitoring Results

Abstract

The spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) on-board ENVISAT is measuring solar irradiances and Earthshine radiances from the UV to the NIR spectral region in nadir, limb and lunar/solar occultation geometry. From these measurements the amount and distribution of various atmospheric constituents are derived (O3, BrO, OClO, SO2, H2CO, NO2, CO, CO2, CH4, H2O, clouds, and aerosols). To assure the quality of these data products at any time during the whole mission a detailed knowledge of the instrument status and behaviour is mandatory. To achieve this a comprehensive monitoring concept has been developed and implemented, involving various dedicated calibration and monitoring measurements. We present selected results from the analysis of these monitoring data. Special emphasis is placed on the performance monitoring for the various light paths and the derivation of degradation correction factors for operational data products.