False Transient Filtering Algorithm Design Document

Meteosat Third Generation (MTG) is being created through cooperation between EUMETSAT and ESA to ensure continuity of high-resolution meteorological data to beyond 2037. The MTG-I imaging satellites will carry the Flexible Combined Imager (FCI) and the Lightning Imager (LI). The Lightning Imager will offer improvements for nowcasting by delivering information on total lightning (Intra Cloud (IC) and Cloud to Ground (CG)). The instrument will bring full hemispheric near real-time total lightning detection capabilities. The benefit of the LI mission is that it will continuously and simultaneously observe total lightning over the hemisphere, providing the information to the users with an extremely high timeliness. The LI mission will be able to detect, monitor, track and extrapolate, in time, the development of active convective areas and storm life cycles -- critical for nowcasting and very short range forecasting of severe weather events. A false transient (FT) is defined as a LI triggered event occurring in the absence of a lightning optical pulse. This release of the document examines and discusses the causes of false transients that are detected by Lightning Imager. A first version of the processing chain aimed at filtering of the false transients at level L1b is presented. The report provides a first description of the algorithms devoted to find false transients caused by random telegraph signal noise. Since the principles of the algorithms aimed at removing jitter on ground are the same of the specific algorithm to be implemented on board, also the baseline algorithm of micro vibration filtering implemented on board is discussed and compared with other viable solutions.