On the Classification of Self-Triggered versus OtherTriggered Lightning Flashes

We present in this paper lightning current measurements and LMA (Lightning Mapping Array) data associated with upward flashes observed at the Sàntis Tower during Summer 2017. The LMA network consists of six stations located in the vicinity of the tower at distances ranging from 100 m to 11 km from it. 20 flashes simultaneously recorded by the current measurement system and the LMA are analyzed. Based on the lightning activity derived from the European Lightning Detection Network (EUCLID) in an area within 30 km from the tower and in a 5-second time window before the start of the flash, all the 20 flashes were classified as `self-triggered' (ST). However, the investigations based on the LMA data reveal that 3 of the flashes were preceded by nearby activity and should be therefore classified as `other-triggered' (OT) flashes. The results suggest that the number of OT flashes inferred from LLS data can be underestimated.