The dataset represents the best knowledge of FCI Spectral Response Functions (SRFs) as of September 2021.
The SRF, as obtained by Thales Alenia Space (France) and ESA, was established by a combination of theoretical modeling and measurements (NIR and IR filters and windows, as well as VIS retinas). The SRF data was shared with the NWP SAF, in order to calculate the corresponding RTTOV coefficients.
For each channel, the SRF was calculated for all detector elements. The set of SRFs was averaged to obtain a single averaged SRF per channel. The SRFs were normalized by dividing the average SRF by its maximum value to obtain a normalized spectral response function.
SRFs are provided as a function of wavelength. The normalized SRFs for all spectral channels are shown in Figure 1.
Note that SRFs are provided for each spectral channel regardless of their spatial sampling configurations. For example, the SRF of VIS0.6 represents the SRF of the products FDVIS0.6 (FDHSI at 1 km) and HRVIS0.6 (HRFI at 0.5 km). The same goes 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 support service.