L. F. Chernogor, K. P. Garmash, Q. Guo, Y. Luo, V. T. Rozumenko, Y. Zheng


Subject and Purpose. The study of the effect that each new Solar eclipse (SE) has on radio wave characteristics is an actual scientific and technical issue. Th e purpose of the present work is to analyze the variations in Doppler spectra (DS), Doppler shift of frequency (DSF), and in the reflected wave amplitude (RWA) that were observed during the SE of June 21, 2020 over the People’s Republic of China.

Methods and Methodology. The observations of HF radio wave characteristics were made using the Harbin Engineering University multi-frequency multipath coherent radio system. The temporal variations in DS, DSF of the main ray and RWA are analyzed further. The variations in the DSF were subjected to a systematic spectral analysis that involved joint application of the windowed Fourier transform, adaptive Fourier decomposition, and the Morlet mother-function-based wavelet transformation.

Results. The SE was accompanied by DS diffuseness resulting from an increase in the number of rays. The DSF temporal variations were observed to be bi-polar and asymmetrical, with extreme DSF magnitudes varying from –11 to –40 mHz and from 22 to 56 mHz. The duration of processes with negative DSF values varied from 50 to 80 min, and the duration of processes with positive DSF changed from 30 to 80 min. The multi-hop propagation (from two to five hops) took place along all propagation paths, with a 360 to 560 km one-hop range. The 4...5 min period quasi-periodic DSF variations showed 20...50 mHz amplitude, and the 8...18 min period variations exhibited 40...100 mHz amplitude. The relative amplitudes of the 4...5 min period quasi-periodic variations in the electron density were observed to be in the 0.3...6.2% range, and the amplitudes of the 8...18 min period variations were found to be in the 1.1...21.7% range. A decrease in the electron density along different propagation paths was observed to vary from –(12...16)% to – (20...26)%.

Conclusions. The characteristic features of the variations in HF radio wave parameters in the ionosphere have been studied during the SE of June 21, 2020 over the People’s Republic of China.

Keywords: Solar eclipse, HF radio wave, ionosphere, oblique radio sounding, Doppler spectrum, Doppler shift, reflected wave amplitude.

1. Chernogor, L.F., 2013. Physical eff ects of solar eclipses in atmosphere and geospace. Kharkiv, Ukraine: V.N. Karazin Kharkiv National University Publ. (in Russian).
2. Le, H., Liu, L., Ren, Z., Chen, Y., and Zhang, H., 2020. Effects of the 21 June 2020 solar eclipse on conjugate hemispheres: A modeling study. J. Geophys. Res.: Space Phys., 125(11). DOI:

3. Zhang, R., Le, H., Li, W., Ma, H., Yang, Y., Huang, H., Li, Q., Zhao, X., Xie, H., Sun, W., Li, G., Chen, Y., Zhang, H., and Liu, L., 2021. Multiple technique observations of the ionospheric responses to the 21 June 2020 solar eclipse. J. Geophys. Res.: Space Phys., 125(12). DOI:

4. Huang, F., Li, Q., Shen, X., Xiong, C., Yan, R., Zhang, S.-R., Wang, W., Aa, E., Zhong, J., Dang, T., and Lei, J., 2020. Ionospheric responses at low latitudes to the annular solar eclipse on 21 June 2020. J. Geophys. Res.: Space Phys., 125(10). DOI:

5. Dang, T., Lei, J.H., Wang, W.B., Yan, M.D., Ren, D.X., and Huang, F.Q., 2020. Prediction of the thermospheric and ionospheric responses to the 21 June 2020 annular solar eclipse. Earth Planet. Phys., 4(3), pp. 231—237. DOI:

6. Patel, K., and Singh, A.K., 2021. Changes in atmospheric parameters due to annular solar eclipse of June 21, 2020, over India. Indian J. Phys. DOI:

7. Wang, X., Li, B., Zhao, F., Luo, X., Huang, L., Feng, P., and Li, X., 2021. Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis. Sensors, 21(4). DOI:

8. Wang, J., Zuo, X., Sun, Y.-Y., Yu, T., Wang, Y., Qiu, L., Mao, T., Yan, X., Yang, N., Qi, Y., Lei, J., Sun, L., and Zhao, B., 2021. Multilayered sporadic-E response to the annular solar eclipse on June 21, 2020. Space Weather, 19(3). DOI:

9. Şentürk, E., Arqim, A.M., and Saqib, M., 2021. Ionospheric total electron content response to annular solar eclipse on June 21, 2020. Adv. Space Res., 67(6), pp. 1937—1947. DOI:

10. Sun, Y.-Y., Chen, C.-H., Qing, H., Xu, R., Su, X., Jiang, C., Yu, T., Wang, J., Xu, H., and Lin, K., 2021. Nighttime ionosphere perturbed by the annular solar eclipse on June 21, 2020. J. Geophys. Res.: Space Phys., 126(9). DOI:

11. Shagimuratov, I.I., Zakharenkova, I.E., Tepenitsyna, N.Y., Yakimova, G.A., and Efishov, I.I., 2021. Features of the Ionospheric Total Electronic Content Response to the Annular Solar Eclipse of June 21, 2020. Geomagn. Aeron., 61, pp. 756—762. DOI:

12. Aa, E., Zhang, S.-R., Shen, H., Liu, S., and Li, J., 2021. Local and conjugate ionospheric total electron content variation during the 21 June 2020 solar eclipse. Adv. Space Res., 68(8), pp. 3435—3454. DOI:

13. Chen, Y., Feng, P., Liu, C., Chen, Y., Huang, L., Duan, J., Hua, Y., and Li, X., 2021. Impact of the annular solar eclipse on June 21, 2020 on BPL time service performance. AIP Adv., 11, id. 115003. DOI:

14. Huang, L., Liu, C., Chen, Y., Wang, X., Feng, P., and Li, X., 2021. Observations and analysis of the impact of annular eclipse on 10 MHz short-wave signal in Sanya area on June 21, 2020. AIP Adv., 11, id. 115317. DOI:

15. Tripathi, G., Singh, S.B., Kumar, S., Singh, Ashutosh K., Singh, R., and Singh, A.K., 2022. Effect of 21 June 2020 solar eclipse on the ionosphere using VLF and GPS observations and modeling. Adv. Space Res., 69(1), pp. 254—265. DOI:

16. Kascheev, S.B., Zalizovski, A.V., Koloskov, A.V., Galushko, V.G., Pikulik, I.I., Yampolski, Yu.M., Kurkin, V.I., Litovkin, G.I., and Orlov, A.I., 2009. Frequency Variations of HF Signals at Long-Range Radio Paths during a Solar Eclipse. Radio Phys. Radio Astron., 14(4), pp. 353—367.

17. Garmash, K.P., Leus, S.G., and Chernogor, L.F., 2011. January 4, 2011 Solar Eclipse Effects over Radio Circuits at Oblique Incidence. Radio Phys. Radio Astron., 16(2), pp. 164—177. DOI:

18. Chen, G., Wu, C., Huang, X., Zhao, Z., Zhong, D., Qi, H., Huang, L., Qiao, L., and Wang, J., 2015. Plasma flux and gravity waves in the midlatitude ionosphere during the solar eclipse of 20 May 2012. J. Geophys. Res. Space Phys., 120(4), pp. 3009—3020. DOI:

19. Uryadov, V.P., Kolchev, A.A., Vybornov, F.I., Shumaev, V.V., Egoshin, A.I., and Chernov, A.G., 2016. Ionospheric Effects of a Solar Eclipse of March 20, 2015 on Oblique Sounding Paths in the Eurasian Longitudinal Sector. Radiophys. Quantum Electron., 59, pp. 431—441. DOI:

20. Cohen, M.B., Gross, N.C., Higginson-Rollins, M.A., Marshall, R.A., Gołkowski, M., Liles, W., Rodriguez, D., and Rockway J., 2018. The lower ionospheric VLF/LF response to the 2017 Great American Solar Eclipse observed across the continent. Geophys. Res. Lett., 45(8), pp. 3348—3355. DOI:

21. Rozhnoi, A., Solovieva, M., Shalimov, S., Ouzounov, D., Gallagher, P., Verth, G., McCauley, J., Shelyag, S., and Fedun, V., 2020. The effect of the 21 August 2017 total solar eclipse on the phase of VLF/LF signals. Earth Space Sci., 7(2). DOI:

22. Guo, Q., Chernogor, L.F., Garmash, K.P., Rozumenko, V.T., and Zheng, Y., 2019. Dynamical processes in the ionosphere following the moderate earthquake in Japan on 7 July 2018. J. Atmos. Solar-Terr. Phys., 186, pp. 88—103. DOI:

23. Guo, Q., Zheng, Y., Chernogor, L.F., Garmash, K.P., and Rozumenko, V.T., 2019. Ionospheric processes observed with the passive oblique-incidence HF Doppler radar. Visnyk of V.N. Karazin Kharkiv National University, Ser. «Radio Physics and Electronics», 30, pp. 3—15. DOI:

24. Guo, Q., Chernogor, L.F., Garmash, K.P., Rozumenko, V.T., and Zheng, Y., 2020. Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018. Radio Sci., 55(2). DOI:

25. Marple JR., S. L., 1987. Digital spectral analysis: with applications. Englewood Cliffs, N. J.: Prentice-Hall.

26. Chernogor, L.F., 2008. Advanced Methods of Spectral Analysis of Quasiperiodic Wave-Like Processes in the Ionosphere: Specific Features and Experimental Results. Geomagn. Aeronom., 48(5), pp. 652—673. DOI:

27. Bryunelli, B.E., and Namgaladze, A.A., 1987. Physics of the ionosphere. Moscow: Nauka Publ. (in Russian).

28. Schunk, R.W., and Nagy, A.F., 2000. Ionospheres: physics, plasma physics, and chemistry. Cambridge: Cambridge University Press. 29. Davies, K., 1969. Ionospheric Radio Waves. Blaisdell Publishing Company. DOI:

29. Davies, K., 1969. Ionospheric Radio Waves. Blaisdell Publishing Company.

Full Text:


Creative Commons License
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)