Statistical Analysis of the Critical Frequency foF2 Dependence
on Various Solar Activity Indices

A. D. Danilov; Данилов А. Д.; N. A. Berbeneva; Бербенева Н. А.

doi:10.31857/S0016794023600588

Statistical Analysis of the Critical Frequency foF2 Dependence on Various Solar Activity Indices

Authors: Danilov A.D.¹, Berbeneva N.A.²
Affiliations:
1. Institute of Applied Geophysics
2. Faculty of Physics, Moscow State University
Issue: Vol 63, No 5 (2023)
Pages: 619-629
Section: Articles
URL: https://rjsvd.com/0016-7940/article/view/650987
DOI: https://doi.org/10.31857/S0016794023600588
EDN: https://elibrary.ru/XYMAUR
ID: 650987

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Abstract

A description of the ionospheric F2-layer critical frequency foF2 dependence on solar activity by
various indices (proxies) has been analyzed. The results of the vertical ionospheric sounding at the Juliusruh
station during 2 winter months (January and February), 2 equinox months (March and October), and a summer
month (June) are considered. Five solar proxies: Ly-α, MgII, Rz, F30, and F10.7 have been analyzed.
The changes in foF2 are compared to the corresponding changes in 1957–1980. The determination coefficient
R2 according to the Fisher F-test is used as a measure of the quality of the description of the foF2 dependence
on SA by each of the proxies. It has been found that a well-pronounced diurnal variation in the R2 value
is observed in winter months: this is higher at the near-noon hours than at night. In other words, all indices
describe the foF2 behavior better in the daytime than at night. A well-pronounced diurnal variation in R2 is
also observed for four proxies in the equinoctial months, whereas that variation is pronounced much less for
Rz: a strong scatter of the R2 values is seen. A diurnal variation in the R2 is absent completely in June: jumps
from one hour to another are observed. This analysis allows us to conclude that the most reliable SA proxies
for description of the foF2 dependence on SA at all LT hours are MgII, F30, and Ly-α.

About the authors

A. D. Danilov

Institute of Applied Geophysics

Email: adanilov99@mail.ru
Moscow, Russia

N. A. Berbeneva

Faculty of Physics, Moscow State University

Author for correspondence.
Email: adanilov99@mail.ru
Moscow, Russia

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