Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events

Ningyu Liu, Joseph R. Dwyer, Julia N. Tilles, Mark A. Stanley, Paul R. Krehbiel, William Rison, Robert H. Brown, Jennifer G. Wilson

Research output: Contribution to journalArticle

Abstract

This paper reports a study to understand the radio spectrum of thunderstorm narrow bipolar events (NBEs) or compact intracloud discharges, which are powerful sources of high-frequency (HF) and very high frequency (VHF) electromagnetic radiation. The radio spectra from 10 kHz to about 100 MHz are obtained for three NBEs, including one caused by fast positive breakdown and two by fast negative breakdown. The results indicate that the two polarities of fast breakdown have similar spectra, with a relatively flat spectrum in the HF and VHF band. The ratio of energy spectral densities in the very low frequency and HF bands is (0.9–5) × 105. We develop a statistical modeling approach to investigate if a system of streamers can explain the main features of fast breakdown. Assuming that the current moment peak and charge moment change of individual streamers vary in the ranges of 5–10 A-m and 5–20 μC-m, respectively, the modeling results indicate that a system of 107–108 streamers can reproduce the current moment, charge transfer, and radio spectrum of fast breakdown. The rapid current variation on a time scale of nanoseconds required for fast breakdown to produce strong HF/VHF emissions is provided by exponentially accelerating and expanding streamers. Our study therefore supports the hypothesis that fast breakdown is a system of streamers. Finally, suggestions are given regarding future streamer simulations and NBE measurements in order to further develop our understanding of NBEs and lightning initiation.

Original languageEnglish (US)
JournalJournal of Geophysical Research: Atmospheres
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

Thunderstorms
thunderstorms
radio spectra
thunderstorm
radio
breakdown
Frequency bands
very high frequencies
Spectral density
Lightning
Electromagnetic waves
Charge transfer
moments
intracloud discharges
electromagnetic radiation
lightning
modeling
very low frequencies
timescale
suggestion

Keywords

  • compact intracloud discharges
  • high-frequency radio emissions
  • lightning
  • narrow bipolar events
  • radio spectrum
  • streamers

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Liu, N., Dwyer, J. R., Tilles, J. N., Stanley, M. A., Krehbiel, P. R., Rison, W., ... Wilson, J. G. (Accepted/In press). Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events. Journal of Geophysical Research: Atmospheres. https://doi.org/10.1029/2019JD030439

Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events. / Liu, Ningyu; Dwyer, Joseph R.; Tilles, Julia N.; Stanley, Mark A.; Krehbiel, Paul R.; Rison, William; Brown, Robert H.; Wilson, Jennifer G.

In: Journal of Geophysical Research: Atmospheres, 01.01.2019.

Research output: Contribution to journalArticle

Liu, Ningyu ; Dwyer, Joseph R. ; Tilles, Julia N. ; Stanley, Mark A. ; Krehbiel, Paul R. ; Rison, William ; Brown, Robert H. ; Wilson, Jennifer G. / Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events. In: Journal of Geophysical Research: Atmospheres. 2019.
@article{e6126aadfd3e45f9b71c21d990def067,
title = "Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events",
abstract = "This paper reports a study to understand the radio spectrum of thunderstorm narrow bipolar events (NBEs) or compact intracloud discharges, which are powerful sources of high-frequency (HF) and very high frequency (VHF) electromagnetic radiation. The radio spectra from 10 kHz to about 100 MHz are obtained for three NBEs, including one caused by fast positive breakdown and two by fast negative breakdown. The results indicate that the two polarities of fast breakdown have similar spectra, with a relatively flat spectrum in the HF and VHF band. The ratio of energy spectral densities in the very low frequency and HF bands is (0.9–5) × 105. We develop a statistical modeling approach to investigate if a system of streamers can explain the main features of fast breakdown. Assuming that the current moment peak and charge moment change of individual streamers vary in the ranges of 5–10 A-m and 5–20 μC-m, respectively, the modeling results indicate that a system of 107–108 streamers can reproduce the current moment, charge transfer, and radio spectrum of fast breakdown. The rapid current variation on a time scale of nanoseconds required for fast breakdown to produce strong HF/VHF emissions is provided by exponentially accelerating and expanding streamers. Our study therefore supports the hypothesis that fast breakdown is a system of streamers. Finally, suggestions are given regarding future streamer simulations and NBE measurements in order to further develop our understanding of NBEs and lightning initiation.",
keywords = "compact intracloud discharges, high-frequency radio emissions, lightning, narrow bipolar events, radio spectrum, streamers",
author = "Ningyu Liu and Dwyer, {Joseph R.} and Tilles, {Julia N.} and Stanley, {Mark A.} and Krehbiel, {Paul R.} and William Rison and Brown, {Robert H.} and Wilson, {Jennifer G.}",
year = "2019",
month = "1",
day = "1",
doi = "10.1029/2019JD030439",
language = "English (US)",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events

AU - Liu, Ningyu

AU - Dwyer, Joseph R.

AU - Tilles, Julia N.

AU - Stanley, Mark A.

AU - Krehbiel, Paul R.

AU - Rison, William

AU - Brown, Robert H.

AU - Wilson, Jennifer G.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - This paper reports a study to understand the radio spectrum of thunderstorm narrow bipolar events (NBEs) or compact intracloud discharges, which are powerful sources of high-frequency (HF) and very high frequency (VHF) electromagnetic radiation. The radio spectra from 10 kHz to about 100 MHz are obtained for three NBEs, including one caused by fast positive breakdown and two by fast negative breakdown. The results indicate that the two polarities of fast breakdown have similar spectra, with a relatively flat spectrum in the HF and VHF band. The ratio of energy spectral densities in the very low frequency and HF bands is (0.9–5) × 105. We develop a statistical modeling approach to investigate if a system of streamers can explain the main features of fast breakdown. Assuming that the current moment peak and charge moment change of individual streamers vary in the ranges of 5–10 A-m and 5–20 μC-m, respectively, the modeling results indicate that a system of 107–108 streamers can reproduce the current moment, charge transfer, and radio spectrum of fast breakdown. The rapid current variation on a time scale of nanoseconds required for fast breakdown to produce strong HF/VHF emissions is provided by exponentially accelerating and expanding streamers. Our study therefore supports the hypothesis that fast breakdown is a system of streamers. Finally, suggestions are given regarding future streamer simulations and NBE measurements in order to further develop our understanding of NBEs and lightning initiation.

AB - This paper reports a study to understand the radio spectrum of thunderstorm narrow bipolar events (NBEs) or compact intracloud discharges, which are powerful sources of high-frequency (HF) and very high frequency (VHF) electromagnetic radiation. The radio spectra from 10 kHz to about 100 MHz are obtained for three NBEs, including one caused by fast positive breakdown and two by fast negative breakdown. The results indicate that the two polarities of fast breakdown have similar spectra, with a relatively flat spectrum in the HF and VHF band. The ratio of energy spectral densities in the very low frequency and HF bands is (0.9–5) × 105. We develop a statistical modeling approach to investigate if a system of streamers can explain the main features of fast breakdown. Assuming that the current moment peak and charge moment change of individual streamers vary in the ranges of 5–10 A-m and 5–20 μC-m, respectively, the modeling results indicate that a system of 107–108 streamers can reproduce the current moment, charge transfer, and radio spectrum of fast breakdown. The rapid current variation on a time scale of nanoseconds required for fast breakdown to produce strong HF/VHF emissions is provided by exponentially accelerating and expanding streamers. Our study therefore supports the hypothesis that fast breakdown is a system of streamers. Finally, suggestions are given regarding future streamer simulations and NBE measurements in order to further develop our understanding of NBEs and lightning initiation.

KW - compact intracloud discharges

KW - high-frequency radio emissions

KW - lightning

KW - narrow bipolar events

KW - radio spectrum

KW - streamers

UR - http://www.scopus.com/inward/record.url?scp=85071740359&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85071740359&partnerID=8YFLogxK

U2 - 10.1029/2019JD030439

DO - 10.1029/2019JD030439

M3 - Article

AN - SCOPUS:85071740359

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9380

ER -