Skip to main content
SpringerLink
Log in

Trends in the Critical Frequency of the F2 Layer during the Recent Decade

  • Published:
Geomagnetism and Aeronomy Aims and scope Submit manuscript

Abstract

Trends in the F2-layer critical frequency foF2 are calculated based on the vertical sounding data at Juliusruh station over a period of 1996–2022. Four solar activity indices: Ly-α, MgII, F10.7mon, and Rz were used. The conclusion drawn previously is confirmed: seasonal (stronger in winter than in summer) and diurnal (stronger in the daytime than at night) variations exist in the foF2 negative trends. It is shown that the results for the first three indices agree very well, whereas the results using Rz provide slightly different results. It has been found that during the recent 5–7 years, the maximum (winter, daytime) negative trends in foF2 became stronger than for the entire considered interval by a factor of 2–3.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.

REFERENCES

  1. Bilitza, D., International Reference Ionosphere 1990, NSSD-C/WDC-A-R&S 90–22, Greenbelt, Maryland: National Space Science Data Center, 1990.

    Google Scholar 

  2. Danilov, A.D., Seasonal and diurnal variations in foF2 trends, J. Geophys. Res.: Space Phys., 2015, vol. 120, pp. 3868–3882. https://doi.org/10.1002/2014JA020971

    Article  Google Scholar 

  3. Danilov, A.D., Global change in parameters of the upper atmosphere and ionosphere of the Earth, in Sistemnyi monitoring ionosfery (System Monitoring of the Earth), Kotonaeva, N.G., Ed., Moscow: Fizmatlit, 2019, pp. 354–416.

  4. Danilov, A.D., Behavior of F2-layer parameters and solar activity indices in the 24th cycle, Adv. Space Res., 2021, vol. 67, pp. 102–110.

    Article  Google Scholar 

  5. Danilov, A.D. and Konstantinova, A.V., Long-term variations in the parameters of the middle and upper atmosphere and ionosphere (review), Geomagn. Aeron. (Eng-l. Transl.), 2020a, vol. 60, no. 4, pp. 397–420.

  6. Danilov, A.D. and Konstantinova, A.V., Trends in foF2 and the 24th solar activity cycle, Adv. Space Res., 2020b, vol. 65, pp. 959–965. https://doi.org/10.1016/j.asr.2019.10.038

    Article  Google Scholar 

  7. Danilov, A.D. and Konstantinova, A.V., A detailed analysis of the behavior of the F2-layer critical frequency prior to magnetic storms, Geomagn. Aeron. (Engl. Transl.), 2022, vol. 62, no. 5, pp. 590–606.

  8. De Haro Barbás, B.F. and Elias, A.G., Effect of the inclusion of solar cycle 24 in the calculation of foF2 long-term trend for two Japanese ionospheric stations, Pure Appl. Geophys., 2020a, vol. 177, pp. 1071–1078.

    Article  Google Scholar 

  9. De Haro Barbás, B.F., Elias, A.G., Fagre, M., and Zossi, B.F., Incidence of solar cycle 24 in nighttime foF2 long-term trends for two Japanese ionospheric stations, Stud. Geophys. Geod., 2020b, vol. 64, pp. 407–418. https://doi.org/10.1007/s11200-021-0548-9

    Article  Google Scholar 

  10. Elias, A.G., Trends in the F2 ionospheric layer due to long-term variations in the Earth’s magnetic field, J. Atmos. Sol.-Terr. Phys., 2009, vol. 71, nos. 14–15, pp. 1602–1609. https://doi.org/10.1016/j.jastp.2009.05.014

    Article  Google Scholar 

  11. Laštovička, J., A review of progress in trends in the mesosphere–thermosphere–ionosphere system, in The 10th Workshop on Long-Term Changes and Trends in the Atmosphere, Hefei, China, 2018.

  12. Laštovička, J., The best solar activity proxy for long-term ionospheric investigations, Adv. Space Res., 2021, vol. 68, no. 6, pp. 2354–2360. https://doi.org/10.1016/j.asr.2021.06.032

    Article  Google Scholar 

  13. Laštovička, J., Progress in investigating long-term trends in the mesosphere, thermosphere and ionosphere, in The 11th Workshop on Long-Term Changes and Trends in the Atmosphere, Helsinki, Finland, 2022a.

  14. Laštovička, J., The optimum solar activity proxy for long-term studies of FoF2, in The 11th Workshop on Long-Term Changes and Trends in the Atmosphere, Helsinki, Finland, 2022b.

  15. Laštovička, J., Akmaev, R.A., Beig, G., Bremer, J., Emmert, J.T., Jacobi, C., Jarvis, M.J., Nedoluha, G., Portnyagin, Y.I., and Ulich, T., Emerging pattern of global change in the upper atmosphere and ionosphere, Ann. Geophys., 2008, vol. 26, no. 5, pp. 1255–1268.

    Article  Google Scholar 

  16. Yue, X., Liu, L., Wan, W., Wei, Y., and Ren, Z., Modeling the effects of secular variation of geomagnetic field orientation on the ionospheric long-term trend over the past century, J. Geophys. Res., 2008, vol. 113, A10301. https://doi.org/10.1029/2007JA012995.566

    Article  Google Scholar 

Download references

ACKNOWLEDGMENTS

The solar indices values were taken from the LISIRD site (https://lasp.colorado.edu). The authors thank A. V. Konstantinova for calculation of the monthly medians of foF2.

Author information

Authors and Affiliations

  1. Institute of Applied Geophysics, 129128, Moscow, Russia

    A. D. Danilov

  2. Department of Physics, Moscow State University, 119991, Moscow, Russia

    N. A. Berbeneva

Authors
  1. A. D. Danilov
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. N. A. Berbeneva
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to A. D. Danilov.

Ethics declarations

The authors declare that they have no conflicts of interest.

Additional information

Translated by A. Danilov

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Danilov, A.D., Berbeneva, N.A. Trends in the Critical Frequency of the F2 Layer during the Recent Decade. Geomagn. Aeron. 63, 113–120 (2023). https://doi.org/10.1134/S0016793222600886

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1134/S0016793222600886

Search

Navigation