Säntis lightning research facility: a summary of the first ten years and future outlook

The Säntis Tower was instrumented in May 2010 to measure currents of lightning discharges striking the structure. Since then, the system has been recurrently updated and expanded. Presently, data associated with lightning striking the tower are collected at six different sites. The facility is equipped with a current measurement system, three electric field stations, an electrostatic field mill, two x‑ray sensors, a high-speed camera, and four slow cameras. This paper presents the latest measurement configuration at the facility. Other temporarily loaned instruments are also briefly described. Furthermore, examples of some of the data that have been gathered and analyzed are given, and an outlook as well as future plans for the facility are presented.

Comparing the Wave Characteristics of Breakdown Pulses of the Lightning Waveforms in the Himalayan Region

We have analyzed the breakdown pulse train with or without the main event in this paper. Among the selected 81 flashes, 36 flashes are starting positively, and 45 are starting negatively. Also, 58 flashes contain positive pulses, and 67 flashes contain negative pulses, whereas 44 flashes contain both positive and negative pulses. Among these 81 flashes, 22 flashes follow the main events, and the rest are isolated events. In this study, we got the main duration of PB pulses as 1.94 ms and the time interval between the breakdown pulse and return stroke as 61.49 ms. On taking each pulse train, we found the rise time to be 2.6 μs, zero-crossing time 14.95 μs, and the time interval between pulses 199.3 μs. The largest pulse amplitude ratio in the preliminary breakdown pulse to the main event return stroke was 0.43.

Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment

The Asia-Pacific Lightning Location Network (APLLN) is a lightning location system consisting of a series of very low-frequency signal detection sites. Since 2018, 16 detection sites have been deployed with an average baseline longer than 1000 km. The detection site used a trigger sampling method to record the lightning signal with a duration of 2 ms and calculates the lightning arrival time based on digital filtering and the Hilbert envelope method. APLLN used a time difference location algorithm and improved Levenberg–Marquardt non-linear least squares iterative algorithm to calculate and optimize the lightning location results. The analysis results of a strong thunderstorm process show that the average detection efficiency of APLLN was 55.34% for intracloud (IC) strokes, 63.55% for cloud-to-ground (CG) strokes and 61.83% for all strokes (IC + CG). The average location error of APLLN for this thunderstorm is 5–10 km.