Speaker
Description
In 2025, the THUNDERMILL02 Electric Field Mill (EFM) instruments were deployed at two high-altitude mountain observatories: Basic Environmental Observatory Musala in Bulgaria (2925 m a.s.l.) and Observatory Lomnický štít, Slovakia (2634 m a.s.l.), complemented by mobile measurement campaigns in the Czech Republic. This contribution presents the first year of operational experience and selected scientific results from these deployments.
We report on the system performance of THUNDERMILL02 under demanding high-altitude conditions and show examples of thunderstorm electric field recordings captured at both observatories. Selected events are cross-correlated with simultaneous data from ionising radiation detectors co-located at the sites, allowing investigation of links between atmospheric electric fields and particle flux variations during thunderstorm activity. Where available, optical camera data provide additional context for selected events, offering visual insight into lightning development.
The three deployments, spanning different orographic and meteorological regimes, cover a wide range of measurement conditions for atmospheric electricity and ionising radiation studies. Unlike conventional electric field mills, THUNDERMILL02 captures both the quasi-static atmospheric electric field and rapid field changes, enabling more detailed multi-instrumental studies of atmospheric electricity and ionising radiation.