Global triangulation of intense lightning discharges

Abstract

A global network of three electromagnetic measurement instruments is used to simultaneously record time series of globally observable E xtremely‐ L ow‐ F requency (ELF) magnetic field disturbances which propagate with little attenuation around the globe within the Earth‐ionosphere cavity. The triangulation of individual lightning flashes results in a picture of the temporal evolution of intense lightning discharge occurrences on the planetary scale during April 1998. The lightning flash charge moments are calculated with the short pulse approximation of the normal mode expansion. The majority of the triangulated lightning discharges exhibit charge moments with a potential to excite mesospheric sprites and ∼5–20% may account for air breakdown at sprite altitudes in ∼50–70 km height.