Calibration comparison between SCIAMACHY and MERIS onboard ENVISAT

We present a comparison of the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and the Medium Resolution Imaging Spectrometer (MERIS) reflectance calibrations at wavelengths between 442 and 885 nm. Results show that SCIAMACHY underestimates the reflectance by /spl sim/13% at 442 nm reaching up to /spl sim/21% at 885 nm as compared to MERIS. We also find a small nonlinear effect for the lowest reflectance. This effect is more evident for pixels over ocean than over land.