New visualization and analysis tools for 3D Lightning Mapping Array data

The 3D Lightning Mapping Array (LMA) is a regional network of VHF antenna stations spaced 5-50 km apart that detect lightning pulses in the 60-66 MHz band. The pulses are timed by GPS. Time-of-arrival reconstruction results in 3D pulse locations, revealing the lightning leader channels (of negative polarity) inside the cloud and toward ground. The detection range of a sensitive network can reach over 250 km from the center. LMAs are used for lightning science, nowcasting of severe weather and airspace safety.

In 2011, the UPC Ebro 3D Lightning Mapping Array in Spain was the first LMA to be installed outside the USA and has collected data for about 11 years. This system was replaced in 2023 by 13 (up to 15) stations spread out mostly across western Catalonia, operated on solar power. Additionally, the Meteorological Service of Catalonia started operating their LMA network in 2024. Each network can operate independently, but data from both networks can be combined to offer the best spatial coverage and resolution of real-time lightning monitoring.

As the duration of processing time-of-arrival into lightning location data goes up exponentially with the number of stations in the network, smart approaches of combining small groups of stations in parallel and pooling the solutions are investigated.

This poster will focus on the capabilities of newly designed interactive lightning visualization and analysis tools for the LMA, developed using the Julia programming language.

It is a suite of tools that focus on (a) lightning flash analysis and general browsing of activity, (b) storm activity evolution analysis, and (c) network performance analysis based on the data. Lightning flash analysis focused on the structure of the lightning flash. Flash grouping is based on DBSCAN clustering, and sparkle activity near the cloud top can be isolated similarly. An automated leader speed using the Theil-Sen slope estimator of points runs efficiently on a large dataset, and can be used to highlight regions of positive and negative polarity in the cloud. The tool also can read cloud-to-ground stroke data from other networks, and Meteosat Third Generation Lightning Imager or GOES Geostationary Lightning Mapper (GLM) to be compared with LMA. The storm activity analysis tool will be based on local 3D flash density and its evolution in time and aims to study trends in 3D activity, rather than the ubiquitously used general flash rate. Lightning leader speed, polarity and the repetition rate of leaders in flashes may hold new information that could turn out to be useful in monitoring the thunderstorm state and potential for severe weather.