Diurnal and seasonal variations in the Schumann resonance parameters at Moshiri, Japan

. The Schumann resonances (SRs) are the ELF electromagnetic phenomena, which are triggered by global lightning activity. The spectral characteristics of the SR modes are characterized by three fundamental factors: (1) resonant mode intensity, (2) central frequency, and (3) Q-factor (damping effect). These parameters are ~stimated by Lorenzian approximation to the SR data observed at Moshiri, Japan. The SR data- used here are equivalently one-year long, and we have paid particular attention to two horizontal magnetic-field components (H 05, Hew). Variations of the different modes (1st (-8 Hz), 2nd (-14 Hz) and 3rd (-20 Hz)) and different field components are presented to study the diurnal and seasonal variations. The intensity variations of the various modes and components show three dominant maxima in the diurnal variation related to lightning activity in south-east Asia (UT -08 h) and America (UT -20 h) with minor effect from Africa (UT -14 h). The largest global lightning activity occurs during the northern hemisphere summer (JJA) with the southern hemisphere summer (DJF) having the least lightning activity. The frequency and Q-factor variations of the different modes and field components at Moshiri are very complicated in structure, but agree remarkably well with those by recent studies mainly based on the Ez and magnetic observations. Similarities and differences are finally discussed between our Moshiri results and the latest ones from Israel.