Eleven Years of Total Lightning Insights From Belgium’s Ground-Based Lightning Location System BELLS

Abstract:
Presented here is a 11-year lightning climatology spanning the years 2013 to 2023, as recorded by the ground-based Belgian Lightning Location System (BELLS). This study delves into not only the spatial and temporal attributes of cloud-to-ground (CG) lightning flashes but also places specific emphasis on assessing the impact of changes in sensor technol-ogy on the system's ability to detect intracloud (IC) lightning. Additionally, the findings are compared with data collected by a comparable network covering Austria and Germany. In Belgium, the mean CG flash densities vary between 0.1 flashes km-2 yr-1 and 1.3 flashes km-2 yr-1, with an average flash density of 0.59 flashes km-2 yr-1. The change of sensor configuration in Belgium, specifically by reducing the distances between sensors, has notably enhanced the detection of cloud pulses. From 2016 onward, there has been a consistent rise in the proportion of cloud discharges, reaching around 95%. In terms of flashes, the IC:CG ratio can reach values as high as 7-8, which is a factor of 2 greater than what is observed in Austria and Germany. Between 2013 and 2020, there was a downward trend in the average negative CG multiplicity, which decreased from 2.2 to a low of 1.25. After 2020, it began to steadily increase again. This trend is similar to what is observed in Austria and Germany. Finally, the study reviews the estimated peak currents for negative first and subsequent CG strokes.