title: Intercomparison of reflectances observed by GOME and SCIAMACHY in the visible wavelength range.
abstract: We compare the Earth reflectances of the spectrometers Global Ozone Monitoring Experiment (GOME) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) over their overlapping wavelength range (240-800 nm). The goal is to investigate the quality of the radiometric calibration of SCIAMACHY using calibrated GOME data as a reference. However, severe degradation of the GOME instrument in the UV since 2001 prevents it from being a reliable reference below 500 nm. Above 500 nm, GOME is reliable and we find substantial disagreement between GOME and SCIAMACHY, of the order of 15%-20%, which we can attribute completely to the current calibration problems of SCIAMACHY. These numbers are supported by a previous study in which SCIAMACHY was compared with the imager Medium Resolution Imaging Spectrometer (MERIS) onboard the Envisat satellite.
authors.affiliation: Royal Netherlands Meterological Institute, De Bilt, The Netherlands. tilstra@knmi.nl
authors.forename: Lieuwe G
authors.initials: LG
authors.lastname: Tilstra
authors.forename: Piet
authors.initials: P
authors.lastname: Stammes