Spectral response characterisation is the most crucial aspect of satellite calibration. The responses are non-linear and may change over the lifetime over an instrument, making it necessary to correct for these changes after launch when producing images from the system. The accuracy of pre-launch spectral response characterisation, and how well the on-orbit changes are understood, directly affects calibration accuracy and the quality of the data products. Even within the same satellite series, spectral response varies by instrument, sometimes dramatically. In fact, spectral response often varies by detector on the same instrument.

Spectral responses are derived for all 12 channels of the SEVIRI instrument. For an explanation of spectral response derivation, see here (PDF, 388 KB).

Spectral responses for Meteosat-9 (MSG-2) can be found here (WinZip, 226 KB). Note: SEVIRI PFM is onboard Meteosat-8, SEVIRI PFM2 is onboard Meteosat-9, SEVIRI FM3 is onboard MSG-3, and SEVIRI FM4 is onboard MSG-4 (data not yet available).
SEVIRI Modulation Transfer Function (MTF) characterisations for MSG-1, MSG-2 and MSG-3 can be found here (WinZip, 1029 KB).