Comments on “Long-Term Variations of Exospheric Temperature Inferred From foF1 Observations: A Comparison to ISR Ti Trend Estimates” by Perrone and Mikhailov

Shun Rong Zhang, John M. Holt, Philip J. Erickson, Larisa P. Goncharenko

Research output: Contribution to journalComment/debatepeer-review

6 Citations (Scopus)


Perrone and Mikhailov (2017, and Mikhailov et al. (2017, have recently examined thermospheric and ionospheric long-term trends using a data set of four thermospheric parameters (Tex, [O], [N2], and [O2]) and solar EUV flux. These data were derived from one single ionospheric parameter, foF1, using a nonlinear fitting procedure involving a photochemical model for the F1 peak. The F1 peak is assumed at the transition height ht with the linear recombination for atomic oxygen ions being equal to the quadratic recombination for molecular ions. This procedure has a number of obvious problems that are not addressed or not sufficiently justified. The potentially large ambiguities and biases in derived parameters make them unsuitable for precise quantitative ionospheric and thermospheric long-term trend studies. Furthermore, we assert that Perrone and Mikhailov (2017, conclusions regarding incoherent scatter radar (ISR) ion temperature analysis for long-term trend studies are incorrect and in particular are based on a misunderstanding of the nature of the incoherent scatter radar measurement process. Large ISR data sets remain a consistent and statistically robust method for determining long term secular plasma temperature trends.

Original languageEnglish
Pages (from-to)4467-4473
Number of pages7
JournalJournal of Geophysical Research: Space Physics
Issue number5
Publication statusPublished - May 2018

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Geophysics


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