Periodicities in fair weather potential gradient data from multiple stations at different latitudes

J. Tacza, K. A. Nicoll, E. Macotela

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6 Citations (SciVal)


Analysis of the variation of the potential gradient (PG) at ground level is important to monitor the global electric circuit and the different solar and geophysical phenomena affecting it. However, this is challenging since several local factors (e.g., meteorological) produce perturbations in the potential gradient. Time series and spectral analysis of PG at several stations can help to minimise local effects so that global effects may be more clearly observed. In this work, for the first time we performed spectral analysis of the potential gradient recorded at several sites located at Vostok, Concordia, Halley and Casleo (Southern Hemisphere), and Sodankyla and Reading (Northern Hemisphere). In order to find the main periodicities and how the amplitude of those periods change as a function of time we use the Lomb-Scargle periodogram and the wavelet transform, respectively. For all PG sites we found periodicities of 0.5-, 1-, ~180- and 365-day. Our results show that the 0.5-day (1-day) periodicity is more prominent during the months of June–July-August (December–January-February). Evidence of ~27- and ~ 45-day periods was also observed at multiple sites. Further analysis using the cross-wavelet transform for PG versus cosmic rays, PG versus Madden-Julian Oscillation index, and PG versus meteorological parameters, show clues that the 27- and 45-day periods are likely related to the solar rotation and Madden-Julian Oscillation, respectively. Furthermore, our results show that during the passages of co-rotating interaction regions, the 27-day period for PG vs cosmic rays XWT is stronger than for the other XWT analysis.

Original languageEnglish
Article number106250
Number of pages17
JournalAtmospheric Research
Early online date18 May 2022
Publication statusPublished - 1 Oct 2022

Bibliographical note

Funding Information:
KAN acknowledges an Independent Research Fellowship funded by the Natural Environment Research Council (NERC) ( NE/L011514/1 and NE/L011514/2 ). JT acknowledges the Polish National Agency for Academic Exchange for funding of the Ulam Program scholarship agreement no PPN/ULM/2019/1/00328/U/00001.

Publisher Copyright:
© 2022 The Authors


  • Atmospheric electricity
  • Global electric circuit
  • Lomb-Scargle periodogram
  • Space weather
  • Wavelet transform

ASJC Scopus subject areas

  • Atmospheric Science


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