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How Saharan dust and elevated convection can produce negative dipole charge structure ?

Year: 2026

Type: article

Abstract: Between 2014 and 2023, the LMA network SAETTA observed 54 thunderstorm days with negative dipole charge structures during African dust flow events on Corsica Island, mainly in the warm season. The spatial and temporal repartition of thunderstorm days provided by SAETTA data show nocturnal events without preferential regions (even land and sea) in negative dipole cases, whereas classical thunderstorms in Corsica with normal tripole charge structure occur mostly on mountains in the daytime. In the case of negative dipole events, METEORAGE data show more intense and frequent CG+ lightnings than classical thunderstorms, and 89.4\% of IC- lightnings. Meanwhile, ERA-5 reanalysis and radiosonde data exhibit dry and warm low levels, with a temperature inversion near the surface, forcing the triggering of elevated convection. This observation could be a consequence of the radiative impact of Saharan dust. This study shows no evidence for the microphysical impact of aerosols. Meteorological data also exhibit huge wind speeds associated with negative dipole thunderstorms.

Source: Atmospheric Research

DOI: 10.1016/j.atmosres.2026.108783

Authors: Gabriel Hausknost, Sylvain Coquillat, Dominique Lambert, Stéphane Pédeboy, Pierre de Guibert, Eric Gonneau