Testing of the IRI Model by Data from Lovozero, Dickson, Tunguska, and Yakutsk Ionospheric Stations

Empirical models are one of effective ways to set and predict a condition of the ionosphere. To estimate an accuracy of such setting it is necessary to test models by means of experimental data. One of most widely used models is IRI (International Reference Ionisphere), however it is insufficiently tested in the region of high latitudes. In the given article results of testing of the model IRI according to vertical sounding on Russian ionosondes, located in subauroral and high-latitude zones in March– April 2016 are presented. Feature of the period is presence of several geomagnetic disturbances. The studied parameter is a critical frequency foF2, the basic analyzed magnitude is the deviation of a model value from experimental one and its relative mean square deviation. Despite increase last years of numbers of ionosondes in a Russian Arctic zone by efforts of AARI, their number is not enough for detailed monitoring. Additionally, it is possible to use receivers of signals of navigation satellites of such systems, as GPS, GLONASS, providing the information about a total electron content (ТЕС). In a number of papers, possibility of use of ТЕС to obtain critical frequencies is shown. In the present paper, confirmation of this possibility is given in subauroral and high-latitude regions. Results are presented for five Russian stations (Lovozero, Salekhard, Dickson, Tunguska,Yakutsk) in comparison with data of reference middle-latitude station Juliustuh. It is shown, that deviations of model values of foF2 from experimental medians in high latitudes are at level of middle-latitude values, relative deviations for instant values of foF2 day by day do not exceed 20–25 %. The ТЕС usage allows decreasing this estimation in 2 times. Values of correlation coefficients between foF2 and ТЕС, defining possibility to use ТЕС for obtaining foF2, lay within 0.6–0.99. The ТЕС usage allows filling absent values of foF2.