Some results of Schumann resonance studies at a low latitude station Agra, India during post period of solar cycle minimum 2008-2009

Abstract

The characteristics of Schumann resonance (SR) have been studied at a low latitude station Agra (geographic latitude 27.2°N, longitude 78°E), India and the results obtained during two periods (01 April 2007 - 31 March 2008 and 01 March 2011 - 29 February 2012) corresponding to pre and post period of solar cycle minimum (SCM) of 2008-2009 are compared. The results show that (i) there is a shift in the peak thunderstorm activity from the month of July in the pre-SCM to August in post-SCM; (ii) the first mode frequency increases with the increasing SCM; and (iii) there are distinct drops in the frequency range dF1 in the months of August and December 2012 corresponding to effective lightning areas during the post-SCM. The seasonal variation of first mode SR frequency shows that it is theoretically dependent on source-observer distance.