Blitzentladungen im österreichischen Alpenraum mit Fokus auf Single-Stroke Flashes

The present paper shows measurement data of cloud-to-ground flashes in the Austrian Alpine region with a focus on single-stroke flashes. The data were recorded over six thunderstorm seasons from 2009 to 2018 within the framework of a research project. The aim of the project was to generate a ground truth dataset of ground strikes of flashes. The used Video and Field Recording System (VFRS) consists of a high-speed camera and an electric field measurement system to be able to optically analyze the spatial and temporal sequences of lightning discharges and record the transient electric field. The VFRS measurements were performed at 33 different measurement locations in the Austrian Alpine region, and a total of 735 cloud-to-ground flashes with negative polarity were recorded on 61 days. For the evaluation, data from the Austrian Lightning Detection and Information System (ALDIS) are correlated with the VFRS data. The percentage of single-stroke flashes influences the multiplicity (strokes per flash), which is relevant, e.g., for the design of lightning protection measures of high voltage systems. The calculated percentages of single-stroke flashes for the present dataset (27%) are compared with previously published values from different countries (12% to 24%). In order to investigate the influence of the thunderstorm organization on the percentage of single-stroke flashes, weather radar data and wind measurements are additionally used and analyzed for the classification of the different thunderstorm types.