Estimation of Charge Transfer During Long Continuing Currents in Natural Downward Flashes Using Single‐Station E‐Field Measurements

Abstract

The amount of charge transferred to ground during long continuing currents in natural downward flashes can be obtained either through direct current measurements or using remote electromagnetic fields, if direct measurements are not feasible. In this study, measurements of a single‐station E‐field antenna were used to estimate charge transfer during continuing currents. With time‐synchronized high‐speed video recordings serving as ground‐truth data for continuing current occurrence, we estimate transferred charge during long continuing currents in 140 natural downward flashes from electric field changes, assuming a simple monopole charge model. We present average parameters for the duration, transferred charge, amplitude, and the average amplitude on five segments along the channel. Further, we perform a simulation to investigate the estimation performance of the monopole charge model, when the cloud charge is spatially extended. Using an extended charge distribution model, we generate single‐station remote field waveforms and infer the charge with the monopole model. Comparison of the known and inferred charge yields estimation errors depending on the leader orientation, its spatial extension, and the observation distance. A Monte Carlo approach is carried out to statistically evaluate parameter deviations. This novel estimation error analysis sheds light on the limitations of the applied simple techniques for charge transfer estimation of long continuing currents using single‐station electric field measurements.

On the Role of Continuing Currents in Lightning‐Induced Fire Ignition

“…(2014) for a flash with CC in New Mexico. Systematic differences in the total duration of the luminosity and the ELF radio signal of flashes with CC has been previously reported by several authors (e.g., Kohlmann et al., 2022; Saba et al., 2006). For example, Kohlmann et al.…”

“…Zhang et al, 2016), which would allow for the ELF radio sensor to again detect it, as reported by Lapierre et al (2014) for a flash with CC in New Mexico. Systematic differences in the total duration of the luminosity and the ELF radio signal of flashes with CC has been previously reported by several authors (e.g., Kohlmann et al, 2022;Saba et al, 2006). For example, Kohlmann et al (2022) reported that the duration of the CC detected by the ELF radio sensor are between 10% and 69% shorter than in the videos.…”

“…Systematic differences in the total duration of the luminosity and the ELF radio signal of flashes with CC has been previously reported by several authors (e.g., Kohlmann et al, 2022;Saba et al, 2006). For example, Kohlmann et al (2022) reported that the duration of the CC detected by the ELF radio sensor are between 10% and 69% shorter than in the videos. They suggested a number of reasons that could explain these differences, including a possible overdub of the E-field change, transfer of charge produced by the leader or a chemical afterglow producing optical emissions.…”

“…For example, Kohlmann et al. (2022) reported that the duration of the CC detected by the ELF radio sensor are between 10% and 69% shorter than in the videos. They suggested a number of reasons that could explain these differences, including a possible overdub of the E‐field change, transfer of charge produced by the leader or a chemical afterglow producing optical emissions.…”

A new electric field mill array with each of the mill’s rotor controlled precisely by a GPS module: Equipment and initial results

“…In numerous studies, a capacitive sensor, which consists of a sensing plate and a grounded one, had been utilized to estimate the transferred charge (Takeuti et al, 1978;Krehbiel et al, 1979;Brook et al, 1982;Qie X et al, 2000;Cui H et al, 2009;Saito et al, 2009;Zhang TL et al, 2009;Fan XP et al, 2014;Saito, 2016;Kohlmann et al, 2017Kohlmann et al, , 2022Haley et al, 2021). A capacitive sensor is designed to measure the electric field change to estimate the transferred charge quantitatively and investigate the charge structure inside a thundercloud.…”