IRSPP | NWP SAF

Infrared Sounder Pre-processor (IRSPP)

Current version: v1.4, June 2026

IRSPP is a software package to process hyperspectral sounder data from the Infra Red Sounder (IRS) instrument on the MTG-S1 and MTG-S2 satellites (first launch in 2025). For details on the instrument and applications, see the IRS Science Plan

Version 1.4 is compatible with the in-orbit MTG-IRS data, as well as the final set of pre-launch test data. The update release includes a new test case (in-orbit data from November 2025), an option to perform spatial averaging, refinements to the output BUFR sequence, python tools for displaying the netCDF and BUFR data and updates to the build scripts.

The near-real-time dissemination stream for IRS is in the form of netCDF-4 files containing Principal Component (PC) compressed spectra. The IRSPP package ingests these files and converts to reconstructed radiances using sets of eigenvectors that accompany the spectra. Options exist for choosing the channel selection, for apodising the spectra, for creating BUFR output and for conversion to alternative PC basis functions. For users who wish to use full-spectral-resolution IRS data to generate their own eigenvectors, the relevant functionality in the IASI PCA deliverable has been transferred to the new package. The IASI PCA package will be withdrawn following the next major release of IRSPP.

If you have feedback on IRSPP, or would like to discuss with the developers, please contact the NWP SAF helpdesk.

Bug reports

IRSPP v1.2: In libirs/irs_read_irsattr_hdf5.f90, users are advised to comment out line 48 containing “call h5tset_cset_f”. This can cause a crash with some versions of the hdf5 library, when IRS attributes are ASCII, not UTF8. Date of report: 21/08/2023. Fixed in v1.3.

Infrared Sounder Pre-processor (IRSPP)

Documentation

Superseded documentation

Reference documentation for current release (IRSPP v1)

Reference documentation for next main release (IRSPP v2)

Test cases

Bug reports