Solar cycle signatures in lightning activity

Abstract

Abstract. The cross-correlation between lightning occurrence and cosmic ray intensity, solar activity and solar wind is examined on a global scale using data from the World Wide Lightning Location Network (WWLLN) for the period 2009 to 2022. The cross-correlation coefficients vary depending on the position on the globe. Positive cross-correlation between lightning occurrence and Sun spot number is found in most of Africa, South and Central America, while in parts of Europe and Southeast Asia the cross-correlation is negative. Positive cross-correlation between lightning occurrence and By component of heliospheric magnetic field is found for Southern part of South America, part of Europe, and northwestern Asia. Possible mechanisms are discussed. Although local weather and climate play a dominant role in lightning occurrence, observations suggest that changes in solar UV radiation during the solar cycle, together with global circulation and atmospheric waves, may modulate lightning occurrence in tropical and subtropical regions, while the polarity of the heliospheric magnetic field, atmospheric circulation and waves affect lightning occurrence more in mid- and high-latitude regions. The observed changes in cosmic ray intensity play an insignificant role in the global occurrence of lightning.