Large-scale validation of SCIAMACHY reflectance in the ultraviolet

In this paper we present an extensive validation of calibrated SCIAMACHY nadir reflectance in the UV (240- 400 nm) by comparison with spectra calculated with a fast ra- diative transfer model. We use operationally delivered near- real-time level 1 data, processed with standard calibration tools. A total of 9 months of data has been analysed. This is the first reflectance validation study incorporating such a large amount of data. It is shown that this method is a valu- able tool for spotting spatial and temporal anomalies. We conclude that SCIAMACHY reflectance data in this wave- length range are stable over the investigated period. In addi- tion, we show an example of an anomaly in the data due to an error in the processing chain that could be detected by our comparison. This validation method could be extremely use- ful too for validation of other satellite spectrometers, such as OMI and GOME-2.