Percentage of Single-Stroke Flashes Related to Different Thunderstorm Types

This study shows an analysis of data from measurements of natural cloud-to-ground lightning performed in Austria between 2009 and 2018. The measurement system consists of a high-speed Video and electric Field Recording System (VFRS). Over the whole period, 735 negative cloud-to-ground flashes were recorded at 33 different locations on 61 individual days. The measurement locations are scattered across the Austrian territory in Alpine and pre-Alpine terrain. Data from the Austrian Lightning Location System (LLS), ALDIS, are correlated with the collected 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 Austria. The percentage of single-stroke flashes among all negative flashes is higher in this study (27 %) than in previous studies from different countries (12 to 24 %). A classification of thunderstorms does not show any dependency of the single-stroke flash occurrence on different thunderstorm types (based on radar data) or underlying meteorological characteristics (based on vertical wind shear computed from weather stations and radiosondes). In contrast, a possible dependency of the occurrence of single-stroke flashes on underlying terrain (Alpine versus pre-Alpine) is noted.