Meteosat Third Generation (MTG) Lightning Imager (LI) Instrument On-ground and In-flight Calibration

The European Meteosat Third Generation (MTG) Lightning Imager (LI) is an instrument on the geostationary MTG Imager satellite series, for which the first satellite is scheduled for launch in 2021.

The MTG series consists of 6 satellites in total: 4 Imager satellites, equipped with the Flexible Combined Imager (FCI) and Lightning Imager (LI) instruments, and 2 Sounding satellites, with the Infrared Sounder (IRS) and Sentinel-4 UVN instruments. EUMETSAT will operate the satellites, instruments and ground systems for MTG.

The Lightning Imager will continuously provide lightning groups and flashes information for almost the complete visible earth disc from a geostationary orbit around 0 degrees longitude in the time period 2021 to 2041. The instrument will measure day and night at a wavelength of about 777.4 nm and will provide triggered event data from lightning optical pulses at a spatial resolution that corresponds to about 4.5 km x 4.5 km at subsatellite point. The instrument also measures and provides background radiance images at least once every minute. The generated high data rates necessitate automated in-orbit calibration to keep the level-1b data products accurate.

In this presentation the Lightning Imager mission objectives, performance requirements and basic instrument detection principles will be described. In addition, the scientific objectives of the performance verification and calibration both prior to launch and in orbit will be discussed. It will be shown how the calibration measurement data generated in orbit are used to keep the level-1b data accurately calibrated.