2022

Kohlmann H., W. Schulz, F. Rachidi:
Estimation of Charge Transfer During Long Continuing Currents in Natural Downward Flashes Using Single-Station E-Field Measurements

Journal of Geophysical Research: Atmospheres, 127, e2021JD036197, doi.org/10.1029/2021JD036197, 2022

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.

No PDF Download

Download Link

Mansouri E., A. Mostajabi, W. Schulz, G. Diendorfer, M. Rubinstein, F. Rachidi:
On the Use of Benford’s Law to Assess the Quality of the Data Provided by Lightning Locating Systems

Atmosphere 13, 552, doi.org/10.3390/atmos13040552, 2022

Lightning causes significant damage and casualties globally by directly striking humans and livestock, by igniting forest fires, and by inducing electrical surges in electronic infrastructure, airplanes, rockets, etc. Monitoring the evolution of thunderstorms by tracking lightning events using lightning locating systems can help prepare for and mitigate these disasters. In this work, we propose to use Benford’s law to assess the quality of the data provided by lightning locating systems. The Jensen–Shannon and Wasserstein distances between the recorded data distribution and Benford’s distribution are used as metrics for measuring the performance of the lightning locating systems. The data are provided by the European lightning detection network (EUCLID) for the years from 2000 to 2020. The two decades consist of three time windows between which the lightning locating system underwent several upgrades to improve the detection of both positive and negative strokes. The analysis shows that the agreement with Benford’s law is consistent with the expected behavior caused by the applied upgrades to the system throughout the years. The study suggests that the proposed approach can be used to test the success of software and hardware upgrades and to monitor the performance of lightning locating systems.

No PDF Download

Download Link

OVE uses cookies to provide you with the best possible service. By using our website, you consent to the use of cookies. Read more about cookies here.