Effect of variations in the solar-wind parameters on thunderstorm activity

Possible correlation between variations of the intensity of lightnings, which are estimated from the flux of thunderstorm-generated VLF-signals, and variations of the solar wind parameters has been investigated. The signals representing the intensity of local thunderstorms in summer and winter are received in Yakutsk (the Eastern Siberia) and in the African World Thunderstorm Center, respectively. The highest correlation coefficient has been obtained between the thunderstorm activity and variations of the solar-wind particle density. This correlation has a season-dependent sign-alternating character. The maximum positive and negative correlation coefficients are observed in August–September and February, respectively; i.e., the manifestation of solar wind density variations in the thunderstorm activity is maximal in the near-equinoctial periods. This may be associated with the peculiarities of the transfer of the magnetospheric electric field “from morning to evening,” which is induced by the solar-wind particle flux, to ionospheric heights.