ИСТИНА

The issues of morphology of high-latitude ionospheric disturbances and their formation mechanisms are the most important and complex when the upper atmosphere response on geomagnetic storms is investigated. In recent years to answer these questions, along with the experimental data and empirical models are increasingly attracted the theoretical models of the Earth’s upper atmosphere. In this research, we present an overview of the ionospheric effects of geomagnetic storms on September 26-30, 2011, March 8-9, 2008, March 17-23, 2013 and 2015 at sub-auroral and high latitudes, obtained both from satellites and ground-based observations, and using Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP). It is carried out: (1) a comparison of model results with observations of ionospheric parameters obtained using different radio physical methods; (2) a study of the formation mechanisms of temporal variations in ionospheric disturbances at different altitudinal, latitudinal, and longitudinal areas of the upper atmosphere; (3) a discussion of possible causes of mismatch in disturbances obtained in the model and according to the observational data. During the recovery storm phases the model results show an increase in the n(O)/n(N2) ratio and a decrease in n(N2) in the middle and subauroral latitudes, resulting in a daytime positive effects in the foF2. Also, it is carried out a comparison of storm effects in the ionosphere, at plasmaspheric heights and in total electron content and given the explanation of the obtained differences. This investigation was supported by RFBR Grant No. 15-35-20364