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Sudden phase anomalies adapting VLF signals of radio stations on the Novosibirsk – Yakutsk and Krasnodar – Yakutsk propagation paths

V.I. Kozlov^1,2 , A.A. Korsakov¹ , R.R. Karimov^1,2 , V.A. Mullayarov^1,2

¹ Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS, Yakutsk, Russia
² Physical Technical Institute of M.K. Ammosov North-Eastern Federal University, Yakutsk, Russia

The phase variations and sudden phase anomalies (SPA) of signals (14,9 kHz) of Novosibirsk and Krasnodar radio navigation stations registered in Yakutsk in 2009 – 2013 for summer and winter daytime propagation conditions are considered. To describe the dependence of the sudden phase anomalies on X-ray flux intensity (0,1 - 0,8 nm) and the solar zenith angle empirical approximated expression of multiple linear regression is used. The model parameters for paths Novosibirsk - Yakutsk and Krasnodar - Yakutsk for winter and summer are estimated. It is shown that the threshold sensitivity of SPA by X-ray flux on both paths is weakly dependent on the season. The phase deviation for fixed values of the X-ray flux and solar zenith angle from summer to winter on the paths increases. For the path Novosibirsk – Yakuts, SPA dependence on the solar zenith angle is clear in summer. For the path Krasnodar – Yakutsk, SPA dependence on the solar zenith angle is less clear in winter, due to specific propagation conditions (large range of longitude and high-latitude VLF propagation). A comparison of the calculated values of SPA model with experimental data for X-ray flares is presented. The possibility of describing the values of the linear trend (the coefficient of determination greater than 0,64), low standard error not exceeding 1,77°/Mm (Novosibirsk) and 2,5°/Mm (Krasnodar) indicate the adequacy of the SPA model and the obtained estimates of the model parameters. For daytime VLF propagation, the X-ray flux variations based on phase of Novosibirsk signals registrated in Yakutsk for individual days are estimated. The X-ray flux calculated by the model is close to the value of the flare radiation (GOES-15 data). For unperturbed conditions, model X-ray flux data agree well with satellite data. For nighttime propagation conditions, this correspondence is broken.

Keywords: solar flare, radio wave propagation, ionosphere D region, sudden phase anomalies

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References:

Al'pert Ya. L., Rasprostranenie elektromagnitnykh voln i ionosfera (Electromagnetic waves propagation and the ionosphere), Moscow: Nauka, 1972, 564 p.
Belen'kii M.I., Orlov A.B., Pronin A.E., Uvarov A.N., O zavisimosti velichiny VFA SDV ot zenitnogo ugla Solntsa na protyazhennykh trassakh v razlichnykh shirotakh (SPA dependence on the Solar zenith angle on great VLF propagation paths in different latitudes), VIII regional'naya konferentsiya po rasprostraneniyu radiovoln (VIII Regional Conference on Radiowave Propagation), Proc. Conf., Saint-Petersburg, 2002, p. 25.
Demykin S.M., Kishchuk V.P., VIII mezhvedomstvennyi seminar po rasprostraneniyu kilometrovykh i bolee dlinnykh voln (Interagency Workshop on Kilometer and Longer Wavelengths Propagation), Abstracts of Papers, Omsk, 1982, p. 17.
Karimov R.R., Kozlov V.I., Korsakov A.A., Mullayarov V.A., Mel'chinov V.P., Variatsii parametrov signalov radionavigatsionnykh stantsii, registriruemykh v Yakutske v diapazone ochen' nizkikh chastot (Variations of very low frequency signal parameters of radio navigation stations, registrated in Yakutsk), Sovremennye problemy distantsionnogo zondirovaniya zemli iz kosmosa, 2012, Vol. 9, No. 4, pp. 57-62.
http://www.tesis.lebedev.ru/sun_flares.html.
Mitra A., Vozdeistvie solnechnykh vspyshek na ionosferu Zemli (Ionospheric effects of Solar flares), Moscow: Mir, 1977, 370 p.
Orlov A.B., Azarnin G.V., Osnovnye zakonomernosti rasprostraneniya signalov SDV-diapazona v volnovodnom kanale Zemlya – ionosfera (Basic consistent pattern of VLF signal propagation in the Earth - Ionosphere waveguide), Problemy difraktsii i rasprostraneniya voln (Problems of Diffraction and Wave Propagation): Book of articles, Leningrad: Izd-vo LGU, 1970, Issue X, pp. 3–107.
Orlov A.B., Pronin A.E., Uvarov A.N., Shirotnaya zavisimost' effektivnogo koeffitsienta poter' elektronov v dnevnoi nizhnei ionosfere po dannym o variatsiyakh fazy SDV-polei i riometricheskogo pogloshcheniya pri VIV (Latitude dependence of the effective electron loss coefficient in the daytime lower ionosphere from the data on variations in the phase of VLF fields and riometer absorption during SID), Geomagnetizm i aeronomiya, 1998, Vol. 38, No. 3, pp. 102-110.
http://satdat.ngdc.noaa.gov/sem/goes/data/new_full/.
Schlyter P., Computing planetary positions - a tutorial with worked examples, available at: http://stjarnhimlen.se/comp/tutorial.html.

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