Number of Single Stroke Flashes in the Alpine Region of Austria

The present analysis shows data of measurements of natural cloud-to-ground lightning performed during warm season thunderstorms in the Alpine region of Austria. These measurements were performed during six years from 2009 to 2018 to generate a ground truth dataset of atmospheric discharges. The used measurement system consists of a high speed video and an electric field recording system (VFRS), to observe the optical properties of lightning discharges and to record the transient electric field. Measurements have been conducted at 33 different measurement locations and 735 negative cloud-to-ground flashes have been recorded during 61 days spread over the whole measurement period. Data of the Austrian Lightning Location System (LLS), ALDIS (Austrian Lightning Detection and Information System), is correlated with the VFRS ground truth data to complete the dataset. These datasets are used to analyze possible reasons for the detected variation of single stroke flashes in the Alpine region of Austria. The calculated values for single stroke flashes of the present analysis are also compared to previously published values (12-24 %) from different countries. Additionally radar data and wind measurements have been analyzed to classify thunderstorm types in order to investigate the effect of thunderstorm organization on their lightning characteristics. Compared to values from the literature the percentage of negative single stroke flashes in this study is higher (27 %). Results of this report shall contribute to a better understanding of atmospheric discharges in general and their behavior in the Alpine region in particular.