Ground Truth Data of Atmospheric Discharges in Correlation with LLS Detections

This paper presents recent ground truth data analyses in the Austrian Alps run by Graz University of Technology in cooperation with Austrian Lightning Detection and Information System (ALDIS). Atmospheric discharges are observed at different measurement locations by using a Video and Field Recording System (VFRS). This system consists of a high speed video camera (2000 frames per second) and a flat plate antenna to measure the electric field. For the present analysis a data set of the measurement periods 2015, 2017 and 2018 was used for validation of the Lightning Location System (LLS) data of ALDIS. In total 463 negative cloud-to-ground (CG) flashes and 1527 negative CG strokes were recorded in Austria during 51 days. Values for LLS location accuracy are in the range of 90 m to 130 m. LLS flash detection efficiencies in the range from 96.08% to 98.62% and stroke detection efficiencies in the range from 76.36% to 85.60% have been determined. Mean multiplicity values determined with the VFRS data are comparable to the results of previous analyses in the Austrian Alps.