Global sprite occurrence locations and rates derived from triangulation of transient Schumann resonance events

[1] We estimated locations and rates of sprite occurrences on a global scale using 1 - 100 Hz ELF magnetic field waveform data obtained at Syowa station in Antarctica and Onagawa observatory in Japan. From the ELF data obtained in a period between June 19, 2001 and January 20, 2002, we identified 715,500 events of transient Schumann resonances (SRs). The locations and polarizations of these parent cloud-to-ground (CG) discharges were determined by a triangulation method. The charge moments of these CG discharges were calculated with a normal mode expansion model of SR waves. From these results and the empirical sprite initiation probability reported by Hu et al. [ 2002], the global occurrence rate of sprites is estimated to be about 720 events/day on average. It is also found that the active regions of sprite occurrences are located in North and South America, Africa and South-East Asia.