The Belgian Lightning Location System (BELLS)

The Royal Meteorological Institute of Belgium (RMI) has been operating a lightning detection network since 1992. Over the past years, the network has undergone upgrades at the level of soft- and hardware. The present-day Belgian Lightning Location System (BELLS) consists out of 14 LS7002 sensors, out of which five are owned by RMI and positioned within Belgium. The sensors detect low frequency (LF) electromagnetic signals generated by lightning in the 1-350 kHz range. Combined with Vaisala’s latest Total Lightning Processor (TLP), the network uses a combination of magnetic direction finding and time-of-arrival for detecting (intra)cloud (IC) lightning pulses and cloud-to-ground (CG) lightning strokes. 
Based on BELLS data of the last 10 years, i.e., 2013-2022, the temporal and spatial distribution of CG lightning will be discussed. In addition, while the CG detection efficiency can be fairly accurately determined through the use of ground-truth video data, this is not as straightforward in case of IC lightning. Hence, in order to evaluate the performance of the cloud lightning detection, the ratio of the number of cloud lightning pulses to the number of CG lightning return strokes can serve as a measure of change in the network’s cloud lightning detection efficiency. The behavior of this ratio is examined with specific attention to the influence of the length of the baseline between the sensors. Finally, estimated peak currents for negative first and subsequent CG strokes and cloud pulses are reviewed.