TEMPORAL VARIATIONS OF THE GLOBAL LIGHTNING ACTIVITY DEDUCED FROM THESCHUMANN RESONANCE DATA

Temporal variations of the global lightning activity were deduced from long-term Schumann resonance (SR) continuous records. The intensities of the horizontal magnetic field component in the vicinity of the fir st, second, and third SR modes were monitored at Tottori observatory ( 35.5 degrees N, 134.33 degrees E) from 1968. Variations of the effecti ve source-observer distance were estimated using the ratios of the int ensities of individual modes. This allowed us to obtain average diurna l variations of the global lightning activity for each month over a on e-year period. The results show that the distances estimated between t he field-site and the effective source are very stable, while the temp oral changes of the fields and the global lightning intensity derived demonstrate substantial variability. Copyright (C) 1996 Elsevier Scien ce Ltd