Thunderstorm ground enhancements observed on Aragats mountain in Armenia in the wintertime

Abstract

Abstract Thunderstorm ground enhancements (TGEs) occur in the spring-autumn seasons at Aragats due to warm air updrafts that cause hydrometeor charging. However, particle detectors recorded three TGEs within 10 hours on February 7, 2023, despite the temperature being −10 °C. Upon analyzing the energy spectra of TGE electrons and gamma rays, it was discovered that the atmospheric electric-field strength above Aragats, at heights 3300–5300 m, could be around 2.1 kV/cm even in winter. We provide details on the fluxes and energy spectra of TGE electrons and gamma rays, as well as discuss models of cloud electrification in winter.