Monitoring and performances evolutions of the 3 in-flight IASI instruments on-board METOP satellites

The EUMETSAT Polar System (EPS) programme is composed of three polar orbiting meteorological METOP satellites. The main payload instrument on-board each METOP is an InfraRed Atmospheric Sounding Interferometer (IASI). METOP-A, the first one of this series, was launched in 2006. Then METOP-B and METOP-C were launched successively in 2012 and 2018. IASI instrument products are disseminated to meteorological institutions for numerical weather prediction, to laboratories for atmospheric and climate studies and also to space agencies for expertise and monitoring. Since their beginning of life, IASI on-board METOP-A and METOP-B continue to perform very well and therefore demonstrate IASI instrument great performances stability and its sturdiness over time. Since July 2019, IASI on-board METOP-C is operational. It will ensure the continuity of good calibrated data dissemination to the user community for the next decade.

The purpose of this paper is to present the current performances status of the 3 in-flight IASI instruments, up to the Level 1 data. The objective is to give a feedback on the validation and the monitoring performed on IASI instruments during its life time. Moreover, during the past few years, some operational improvements were applied like the update of the on-board non-linerity correction for the 3 instruments. The impact of this new correction will be presented, also the reprocessing of a huge amount of IASI-A data for climate series.

New improvements will be assessed, like the impact on the spectral calibration monitoring of the new release of the GEISA spectroscopic database and the 4A/OP atlases or improvements of inter-comparison techniques.