An evaluation of the Worldwide Lightning Location Network (WWLLN) using the National Lightning Detection Network (NLDN) as ground truth

Abstract

. The WWLLN cloud-to-ground detection efficiency is found to be strongly dependent on peak current and polarity, attaining values larger than 10% (35%) for currents stronger than ±35 kA (−130 kA) and values less than 2% for currents between 0 and −10 kA. The location accuracy is found to have a northward and westward bias, with average location errors of 4.03 km in the north-south and 4.98 km in the east-west directions, respectively. The WWLLN is shown to have strong limitations in capturing the diurnal cycle, missing both the timing of the maximum and minimum lightning activity (around 1600 and 0900 LT, respectively), and the amplitude of the cycle as well. It is found that in 3 h intervals, the number of flashes in the WWLLN has some proportionality to the number of flashes in the NLDN, suggesting that the WWLLN has strong potential for meteorological applications.

Preliminary Study on Features of Lightning Discharge around Japan Using World Wide Lightning Location Network Data

“…The dispersed waveform (the so-called "sferic") of the lightning impulse is processed at each receiving site and the location of the lightning is determined based on the time of group arrival of the VLF waves, detected at more than five stations (Dowden et al 2002). The WWLLN algorithm can detect lightning with a 5-km spatial accuracy and 15-µs temporal accuracy, and its detection efficiency is 11% for all strokes and > 30% for more powerful strokes (Rodger et al 2004;Abarca et al 2010). …”

“…Because detection efficiency is higher for stronger strokes (Rodger et al 2004;Abarca et al 2010) and because the minimum detectable stroke energy of each lightning stroke depends on the minimum observable energy of each WWLLN station (Hutchins et al 2012b), the reliability of data for weak stroke energy is considered insufficient. Therefore, we focus on lightning with strong stroke energy.…”

Natural Field Electromagnetics Using a Partially Known Source: Improvements to Signal to Noise Ratios

“…Hutchins et al (2012) reported WWLLN timing errors to be within 10 microseconds and location accuracies in the order of the wavelength of the radiation (10-15 km). Abarca et al (2010) reported WWLLN detection efficiencies of 30 to 50% for cloud-to-ground strokes (CG) and intra-cloud strokes (IC) above 40 kA, and 10 to 15% for all global CG strokes. The WWLLN also provide lightning stroke power estimates integrated over a 1 ms waveform (Hutchins et al, 2012).…”

Sprite possibly produced by two distinct positive cloud-to-ground lightning flashes

“…The VLF sensors detect impulsive signals from lightning discharges (lightning radiates electromagnetic power from a few hertz to several hundred megahertz, but the bulk of the energy is located in VLF). The WWLLN uses the group arrival time (TOGA) from at least 5 WWLLN sensors to determine the lightning location (Pan et al 2009;Abarca et al 2010;Bovalo et al 2014). The system provides global lightning and a global map with lightning positions updated every 10 min.…”