Atmospheric Conditions, Electric Fields, and Thunderstorm Ground Enhancements at Aragats

Abstract

The Aragats High-Altitude Research Station (3200 m a.s.l.) combines meteorological, atmospheric electric, and particle flux measurements, providing a unique setting for investigating thunderstorm ground enhancements (TGEs) and recent environmental variability. We analyze one-minute observations from 2012 to 2025, first focusing on the meteorological and electric-field conditions controlling TGEs and then on trends in air temperature and daytime solar radiation. From an archive of 610 TGEs, a quality-controlled subset of 284 events with particle flux enhancements larger than 10 percent was selected. Comparisons of May, August, and October show that strong near surface electric fields alone are insufficient for frequent TGEs. May combines strong-field conditions with low cloud bases and shows a pronounced inverse relation between TGE occurrence and cloud-base distance. Thus, TGE occurrence is jointly controlled by thundercloud electrification and cloud-to-detector distance, while the recent warming tendency cannot be attributed to increased measured short-wave radiation. The annual mean air temperature shows a statistically significant positive trend, whereas daytime solar radiation shows a significant negative trend. Thus, warming at Aragats cannot be explained solely by variations in solar radiation.