Detection of multiple TGFs produced by the same thunderstorm system

Abstract:

The new on-board configuration of the AGILE satellite enhanced the detection of Terrestrial Gamma-ray Flashes (TGFs) of about one order of magnitude (up to ~100 TGFs/month), making the MiniCALorimeter more sensitive to events, especially on shorter time scales. As a direct consequence of the increased statistics, we observe several cases of more TGFs produced by the same thunderstorm system. Among the 179 TGFs detected in the period 23/03/2015 - 23/06/2015 we identify 15 pairs of consecutive TGFs occurring <2 min one from each other and coming from a <300 km geographic region. Moreover, we find 5 pairs of events coming from the same region and separated in time by an entire orbital period, which correspond to TGFs detected as the satellite passes over the same still active geographic area during its subsequent orbit. We take advantage of data acquired by the geostationary meteorological satellites to establish whether these pairs are produced by the same thunderstorm system and to characterize the related meteorological scenario, providing a further confirmation that a single thunderstorm is capable of producing multiple TGFs.