Validation of the Meteosat storm detection and nowcasting system Cb-TRAM with lightning network data – Europe and South Africa

Abstract

In this paper, recent changes to the Meteosat thunderstorm TRacking And Monitoring algorithm (Cb-TRAM) are presented as well as a validation of Cb-TRAM against data from the European ground-based LIghtning NETwork (LINET) of Nowcast GmbH and the South African Weather Service Lightning Detection Network (SAWS LDN). Validation is conducted along the well-known skill measures probability of detection (POD) and false alarm ratio (FAR) on the basis of Meteosat/SEVIRI pixels as well as on the basis of thunderstorm objects. The values obtained demonstrate specific limitations of Cb-TRAM, as well as limitations of satellite methods in general which are based on thermal emission and solar reflectivity information from thunderstorm cloud tops. Although the climatic conditions and the occurrence of thunderstorms are quite different for Europe and South Africa, quality score values are similar. Our conclusion is that Cb-TRAM provides robust results of well-defined quality for very different climatic regimes.