Articles | Volume 16, issue 5
Research article
14 Mar 2016
Research article |  | 14 Mar 2016

Semi-annual oscillation (SAO) of the nighttime ionospheric D region as detected through ground-based VLF receivers

Israel Silber, Colin Price, and Craig J. Rodger


Total article views: 2,426 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
1,404 937 85 2,426 62 61
  • HTML: 1,404
  • PDF: 937
  • XML: 85
  • Total: 2,426
  • BibTeX: 62
  • EndNote: 61
Views and downloads (calculated since 04 Nov 2015)
Cumulative views and downloads (calculated since 04 Nov 2015)


Saved (final revised paper)

Latest update: 21 May 2024
Short summary
We report for the first time that the semi-annual oscillation (SAO) is one of the dominant oscillations in the nighttime lower ionosphere, using ground-based measurements of VLF signals reflected off the lower part of the ionosphere. We conclude that the origins of this oscillation are oscillatory changes of the D region's electrical characteristics, driven by NOx transport from the lower thermosphere. This oscillation should be considered in lower ionospheric and VLF wave propagation models.
Final-revised paper