In-flight calibration of the SCIAMACHY solar irradiance spectrum

Abstract ESA's new Earth observation satellite ENVISAT was launched successfully on 2002-02-28. Among nine other instruments it is carrying the new imaging spectrometer SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography). This paper covers part of the calibration and validation efforts during the first seven months of SCIAMACHY in orbit with special emphasis on the application of the internal white light source for radiometric calibration. The solar irradiance spectrum measured by SCIAMACHY is presented and compared with a solar spectrum derived by R. L. Kurucz as well as with solar irradiances measured by the UARS instruments SOLSTICE and SUSIM.