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 (Geograph. lat. 27.2^oN, long. 78^oE), 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. Our results show that (i) there is a shift in the (ii) peak thunderstorm activity from the month of July in the pre-SCM to August in post-SCM, (iii) the first mode frequency increases with the increasing SCM, and 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. We also study the seasonal variation of first mode SR frequency and show theoretically it’s dependence on source-observer distance.