Abstract and keywords
Abstract (English):
We report the results of the analysis of annual variations in daily electron density (N) for various solar activity conditions — minimum, rise, and maximum (2007–2014) — obtained from digisonde measurements at the ionospheric station Norilsk (69.4° N, 88.1° E). New coefficients of the known semi-empirical model (SEM) describing the connection between N and thermosphere characteristics are calculated to identify regularities of these variations exactly at Norilsk station. The height changes of annual variations in the noon electron density N are obtained in the F1 region (120–200 km). The experimental data approximation describes N quite satisfactorily at these heights in the daytime of different seasons under different solar activity conditions. It is shown that in the years of solar minimum at all heights of the F1 layer the tendency remains for maximum N in summer and for minimum N in winter. In later years and in the year of maximum solar activity, a characteristic feature of the behavior of N is the change in the phase of the annual variation by 180° in the range of heights from 170 to180 km: maximum N is observed in winter; and minimum, in summer.

annual variations, electron density, semi-empirical model
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1. Bilitza D., Altadill D., Truhlik V., Shubin V., Galkin I., Reinisch B., Huang X. International Reference Ionosphere 2016: From ionospheric climate to real-time weather predictions. Space Weather. 2017, vol. 15, pp. 418-429. DOI: 10.1002/ 2016SW001593.

2. Picone J.M., Hedin A.E., Drob D.P., Aikin A.S. (GTD7-2000) NRLMSIS-00 Empirical model of the atmosphere; statistical comparisons and scientific issues. J. Geophys. Res. 2002, vol. 107, no. A12, p. 1469. DOI:https://doi.org/10.1029/2002JA009430.

3. Shchepkin L.A., Kushnarenko G.P., Freizon I.A., Kuznetsova G.M. The electron density connection with the thermospheric state in the middle ionosphere. Geomagnetizm i aeronomiya [Geomagnetism and Aeronomy].1997, vol. 37, no. 5, pp. 106-113. (In Russian).

4. Shchepkin L.A., Kushnarenko G.P., Kuznetsova G.M. Annual variation of the electron density in the ionosphere F1 region. Solnechno-zemnaya fizika [Solar-Terrestrial Physics]. 2005, iss. 7, pp. 62-67. (In Russian).

5. Shchepkin L.A., Kuznetsova G.M., Kushnarenko G.P., Ratovsky K.G. The interpretation of the electron density measurements with the semiempirical model help. Solnechno-zemnaya fizika [Solar-Terrestrial Physics]. 2007, iss. 10, pp. 89-92. (In Russian).

6. Shchepkin L.A., Kuznetsova G.M., Kushnarenko G.P., Ratovsky K.G. Approximation of data on measurements of electron concentration in the middle ionosphere at low solar activity. Solnechno-zemnaya fizika [Solar-Terrestrial Physics]. 2008, no. 11, pp. 66-69. (In Russian).

7. Tobiska W.K., Eparvier F.G. EUV97: Improvements to EUV irradiance modeling in the soft X-rays and EUV. Solar Phys. 1998, vol. 147, no. 1. pp. 147-159. DOI:https://doi.org/10.1023/A: 1004931416167.

8. URL: http://wdc.kugi.kyoto-u.ac.jp (accessed September 26, 2018).

9. URL: http//ckp-rf.ru/ckp/3056 (accessed September 26, 2018).

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