Environmental Influences on Measurements with Electric Field Meters for Lightning Observation

Abstract:
Prevailing weather forecasts can provide a certain level of accuracy when it comes to the prediction of thunderstorms. However, it is still impossible to determine exactly when or where cloud-to-ground lightning will strike Earth’s surface. To assess the risk of lightning, parameters shall be established by recording the electric field of the atmosphere using electric field meters and correlating the data with weather radar data and lightning location system data. Such measurements with electric field meters can be affected by various environmental influences such as buildings, vegetation or the elevation level. To evaluate these influences measurements have been carried out from June 2023 to November 2023. Simultaneous measurements using two identical field meters were conducted at different locations during two measurement campaigns, one on flat terrain at Campus Inffeld of Graz University of Technology, Austria and one on elevated terrain at Schöckl mountain near Graz and the Koralpe in Carinthia, Austria. The measurements have been conducted under fair-weather conditions (i.e., cloudless sky) for a time period of 60 minutes. The field enhancement factors for the Inffeldgasse 33 building at Campus Inffeld (23 m.a.s.l.) and the Schöckl mountain (1445 m.a.s.l.) has been determined and compared to each other to evaluate the field enhancement effect due to structural influences and the elevation level. Further, the shadowing effect on the electric field has been investigated to determine an optimal distance for the electric field meter towards higher objects such as buildings or trees.