Measurement of ELF emission in the upper atmosphere over Kolkata due to Schumann resonances*

32-34The discrete spectra of the transmission frequencies at 8, 14, 20, ... Hz, due to Schumann resonances are generated by electromagnetic emission from the lightning strokes and can be regarded as excitation of an AC global circuit. In this paper, the results of an attempt to detect experimentally these discrete signals at Kolkata (lat. 22°34'N) are presented. Some frequency changes of 10%-20% about the peak values are found to be present in the observed data which may be attributed by the uncertainties arising from spatial distribution of lightning sources exciting the Schumann resonance modes