FCI A Spot

MTG FCI Spectral Response Functions released


FCI A Spot
FCI A Spot

The Meteosat Third Generation Flexible Combined Imager (FCI) Spectral Response Functions are now available for user familiarisation.

Last Updated

26 September 2023

Published on

08 April 2022

The dataset represents the best knowledge of the FCI Spectral Response Functions (SRF) in September 2021.

The SRF, as obtained by Thales Alenia Space (France) and ESA, has been established by a combination of theoretical modelling and measurements (NIR and IR filters and windows, as well as VIS retinas). The SRF data have been shared with the NWP SAF, in order to calculate the corresponding RTTOV coefficients.

For each channel, the SRF has been computed for all detector elements. The set of SRFs have been averaged to get a single-averaged SRF per channel. The SRFs have been normalised by dividing the average SRF by its maximum value in order to obtain a normalised spectral response function.

The SRFs are provided as a function of the wavelength. The normalised SRF for all the spectral channels are presented in Figure 1.

MTG FCI Spectral Response Functions
Figure 1: Normalised spectral response functions for the FCI spectral channels

Note that the SRFs are provided for each spectral channel regardless of their spatial sampling configurations. For instance, the SRF of VIS0.6 represents the SRF of FDVIS0.6 (FDHSI at 1 km) and HRVIS0.6 (HRFI at 0.5 km) products. The same is true for NIR2.2, IR3.8 and IR10.5.

Users can access the Spectral Response Functions via our sftp site:


For more information, contact our User Service Helpdesk.