The amplitudes of lightning sferics are commonly used for data analyses, for example, in lightning location networks. This contribution investigates the coherency of lightning sferics, which is calculated from the phase of the analytic complex signal. The complex signal is obtained from the Hilbert transform with the recorded signal as the input signal. This analytic signal is composed of amplitudes with corresponding phases. Rigorous selection criteria are applied to ensure that consistent events are used to calculate distance-dependent average sferics waveforms which are summarized in waveform banks for the amplitude and coherency. The impulse response to lightning flashes is derived from an averaged waveform which is used to detect individual lightning events. It is shown that the coherency waveform bank is in general agreement with the amplitude waveform bank, that is, the relative arrival times of the ground and sky waves. The coherency waveform bank exhibits the same number of skywaves on the logarithmic scale, but a less attenuated ground wave when compared to the amplitude waveform bank. The results of this study show that the phase of sferics offers additional information to amplitudes, which could potentially be used for the interferometric lightning location with long-range lightning detection networks.
Original languageEnglish
Article numbere2021RS007347
JournalRadio Science
Issue number5
Publication statusPublished - 19 May 2022

Bibliographical note

Funding Information:
The work of X.B. was sponsored by URSA under the project Grant No. EA‐EE1250. The work of M.F. was sponsored by the Royal Society (UK) grant NMG/R1/180252 and the Natural Environment Research Council (UK) under grants NE/L012669/1 and NE/H024921/1. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement 722337. X.B. conducted the analysis and wrote the paper, and M.F. assisted with conceiving the concept of the paper. The authors wish to thank Stephane Pedeboy at Meteorage for access to selected lightning flash data, the team of the Laboratory Souterrain a Bas Bruit (LSBB) in Rustrel for their generous hospitality, Adam Peverell for extracting and communicating the data, Yuqing Liu, Mert Yücemöz, Serge Soula, Jean‐Louis Pinçon, Franck Elie, and Matthieu Garnung for assisting with the acquisition of the electric field data used in this study, and the reviewers for their assistance to improve the quality of the manuscript.

Publisher Copyright:
© 2022. The Authors.


  • atmospheric and space electricity
  • electromagnetic noise
  • lightning

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Earth and Planetary Sciences(all)
  • Electrical and Electronic Engineering


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