Correlated Disturbances of the Upper and Lower Ionosphere from Synchronous Measurements of Parameters of GNSS Signals and VLF Radio Signals
This is a study of the spatiotemporal distribution of midlatitude disturbances of the upper and lower ionosphere in the European zone during a strong geomagnetic storm and strong X-ray flare using data of synchronous measurements of the parameters of global navigation satellite system (GNSS) signals and very low-frequency (VLF) radio signals. It has been shown that the contribution of electron concentration at different altitudes to the total electron content of the ionosphere can vary significantly depending on the type of heliogeophysical disturbances. A combined analysis of GNSS signals and VLF radio signals makes it possible to study the mechanisms of coupling between the upper and lower ionospheric disturbances and the dynamics of ionospheric disturbances in the horizontal and vertical directions.
This study was conducted within State research targets AAAA-A17-117112350014-8 and 0146-2015-0017.
The authors are sincerely grateful to Madrigal (http://www.openmadrigal.org/), UK Solar Data Centre (https://www.ukssdc.ac.uk/cgi-bin/digisondes/ cost_database.pl), and Kiel Longwave Monitor (http://www.lf-radio.de/) for providing us with geophysical data and to Johns Hopkins University Applied Physics Laboratory for providing us with DMSP satellite data (http://ssusi.jhuapl.edu/).
- 2.Gavrilov, B.G., Zetser, Yu.I., Ryakhovskii, I.A., Poklad, Yu.V., and Ermak,V.M., Remote sensing of ELF/VLF radiation induced in experiments on artificial modification of the ionosphere, Geomagn. Aeron. (Engl. Transl.), 2015, vol. 5, no. 4, pp 450–456. https://doi.org/10.7868/S0016794015040045
- 3.Han, F., Cummer, S.A., Li, J., and Lu, G., Daytime ionospheric D region sharpness derived from VLF radio atmospherics, J. Geophys. Res., 2011, vol. 116, no. 5. https://doi.org/10.1029/2010JA016299
- 4.Maurya, A.K., Veenadhari, B., Singh, R., et al., Nighttime D region electron density measurements from ELF–VLF tweek radio atmospherics recorded at low latitudes, J. Geophys. Res., 2012, vol. 117, no. A11. https://doi.org/10.1029/202JA017876
- 5.Gavrilov, B.G., Zetser, Yu.I., Lyakhov, A.N., Poklad, Yu.V., and Ryakhovskii, I.A., Spatiotemporal distributions of the electron density in the ionosphere by records of the total electron content and phase of VLF radio signals, Geomagn. Aeron. (Engl. Transl.), 2017, vol. 57, no. 4, pp. 461–470. https://doi.org/10.7868/S001679401704006X
- 7.Borries, C., Mahrous, A.M., Ellahouny, N.M., and Badeke, R., Multiple ionospheric perturbations during the Saint Patrick’s Day storm 2015 in the European–African sector, J. Geophys. Res.: Space Phys., 2016, vol. 121, no. 11, pp. 11333–11345. https://doi.org/10.1002/2016JA023178 ADSCrossRefGoogle Scholar
- 10.Wait, J.R. and Spies, K.P., Characteristics of the Earth–ionosphere waveguide for VLF radio waves, NBS Technical Note no. 300, 1964.Google Scholar
- 11.Kumar, A. and Kumar, S., Solar flare effects on D‑region ionosphere using VLF measurements during low- and high-solar activity phases of solar cycle 24, Earth Planets Space, 2018, vol. 70, no. 1, id 70. https://doi.org/10.1186/s40623-018-0794-8