Arctic lightning during solar wind disturbance
In the authors' words
Abstract The mechanisms modulating lightning are not entirely understood. While electric fields within thunderclouds are insufficient to initiate lightning, solar-wind activity has been proposed as one of the possible external drivers, operating via energetic particles and modifications to the global atmospheric electric circuit. However, solar-wind impacts on lightning activity remain underexplored, particularly at high latitudes. Here, we analyze statistical relationships between solar-wind activity and lightning over Fennoscandia. During solar cycle 23, annual lightning activity at 62–67°N correlates significantly with energetic proton fluxes and, at 65–67°N, with high-speed solar wind streams. However, a short-term analysis reveals weaker relationships. An event-based analysis demonstrates that within specific northern latitude bands, high-speed streams significantly double the probability of extreme-lightning days when suitable convective cloud conditions are already established. These findings demonstrate that solar-wind influence on lightning activity is not driven by a single mechanism, but is a sporadic, regionally structured phenomenon strictly constrained by local meteorological conditions and, surprisingly, emerges only on long timescales.
Appeared: Thursday, September 24. Communications Earth & Environment. Peer-reviewed journal.