Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 5 2005 10.5194/acpd-5-8925-2005 http://www.atmos-chem-phys-discuss.net/5/8925/2005/ http://www.atmos-chem-phys-discuss.net/5/8925/2005/acpd-5-8925-2005.html http://www.atmos-chem-phys-discuss.net/5/8925/2005/acpd-5-8925-2005.pdf 8925 8977 2005-09-19 SCIAMACHY Level1 data: Calibration concept and in-flight calibration G. Lichtenberg Q. Kleipool J. M. Krijger G. van Soest R. van Hees L. G. Tilstra J. R. Acarreta I. Aben B. Ahlers H. Bovensmann K. Chance A. M. S. Gloudemans R. W. M. Hoogeveen R. Jongma S. Noël A. Piters H. Schrijver C. Schrijvers C. E. Sioris J. Skupin S. Slijkhuis P. Stammes M. Wuttke SRON National Institute of Space Research, Utrecht, the Netherlands Royal Netherlands Meteorological Institute (KNMI), de Bilt, the Netherlands Institute of Remote Sensing (IfE), University of Bremen, Germany TNO Science and Industry, Delft, the Netherlands DLR-DFD/IMF, Weßling, Germany Harvard-Smithsonian Center for Astrophysics (SAO), Cambridge, USA now at: Royal Meteorological Institute Netherlands (KNMI), de Bilt, the Netherlands This paper discusses the basic concept of the calibration of the SCIAMACHY instrument and remaining open issues. SCIAMACHY is a scanning Limb/Nadir spectrometer covering the wavelength range from 212 nm to 2386 nm. It was launched on-board ENVISAT in February 2002. In general the instrument performance is excellent: It performs as tested on ground and there is only very minor degradation in time. The only exception is the unexpected formation of water ice on the infrared channels 7 and 8 that attenuates the signal and a light leak in channel 7. Both effects will be discussed. In the paper we will explain all individual calibration steps needed to come to a wavelength calibrated spectrum of the Earth reflectance. Open points in the calibrations and latest improvements, such as the new radiometric calibration will also be treated.