Map of low-frequency electromagnetic noise in the sky

Martin Füllekrug, Andrew Mezentsev, Robert Watson, Stéphane Gaffet, Ivan Astin, Nathan Smith, Adrian Evans

Research output: Contribution to journalArticlepeer-review

12 Citations (SciVal)


The Earth's natural electromagnetic environment is disturbed by anthropogenic electromagnetic noise. Here we report the first results from an electromagnetic noise survey of the sky. The locations of electromagnetic noise sources are mapped on the hemisphere above a distributed array of wideband receivers that operate in a small aperture configuration. It is found that the noise sources can be localized at elevation angles up to ∼60° in the sky, well above the horizon. The sky also exhibits zones with little or no noise that are found toward the local zenith and the southwest of the array. These results are obtained by a rigorous analysis of the residuals from the classic dispersion relation for electromagnetic waves using an array analysis of electric field measurements in the frequency range from ∼20 to 250 kHz. The observed locations of the noise sources enable detailed observations of ionospheric modification, for example, caused by particle precipitation and lightning discharges, while the observed exclusion zones enable the detection of weak natural electromagnetic emissions, for example, from streamers in transient luminous events above thunderclouds.

Original languageEnglish
Pages (from-to)4648-4653
Number of pages6
JournalGeophysical Research Letters
Issue number11
Early online date19 May 2015
Publication statusPublished - 16 Jun 2015


  • array analysis
  • atmospheric and space electricity
  • electromagnetic noise


Dive into the research topics of 'Map of low-frequency electromagnetic noise in the sky'. Together they form a unique fingerprint.

Cite this