Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse

Nathaniel Frissell, J. D. Katz, S. W. Gunning, J. S. Vega, Andrew Gerrard, G. D. Earle, M. L. Moses, M. L. West, J. D. Huba, P. J. Erickson, E. S. Miller, R. B. Gerzoff, W. Liles, H. W. Silver

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium- and high-frequency radio propagation by the Solar Eclipse QSO Party citizen science experiment organized by the Ham Radio Science Citizen Investigation ( This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed ±0.3 hr on 1.8 MHz, ±0.75 hr on 3.5 and 7 MHz, and ±1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at h≥125 km altitude with elevation angles θ≥22°, while 14 MHz signals refracted at h < 125 km with elevation angles θ < 10°.

Original languageEnglish (US)
Pages (from-to)4665-4674
Number of pages10
JournalGeophysical Research Letters
Issue number10
StatePublished - May 28 2018

All Science Journal Classification (ASJC) codes

  • Geophysics
  • General Earth and Planetary Sciences


  • HF propagation
  • amateur radio
  • citizen science
  • ham radio
  • ionosphere
  • solar eclipse


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