First Results for the Influence of Two Geomagnetic Storms during 10-12 May 2024 On Mid-latitude Ionosphere

Abstract

The main idea of this study is to analyze the ionospheric anomalies in selected points related to the extreme geomagnetic storm which occurred during the period 10–12 May 2024. In the present research, data of the critical frequency of the F2 region (foF2) from the vertical sounding of ionospheric station Rome (Italy) and foF2 data for the territory of Sofia (Bulgaria) obtained by empirical modelling were used. The selection of Rome ionospheric station is related to the fact that this ionosonde is located at the geographic latitude coinciding with the latitude of Sofia, which suggests similar characteristics of the ionosphere. In order to evaluate the type of response (positive or negative), the relative deviation of the values was used, taking into account the influence of the local time for the individual points (1 hour). The results of the of the ionospheric response analysis show a well expressed negative response, more significant at Rome station. Another interesting result related to the inertia of the ionosphere is expressed in the observed response delay depending on the onset of the geomagnetic storm. From the comparison of the measured data and those obtained through the empirical model it can be seen that for the purposes of ionospheric forecasting, the model is able to describe the behaviour of the ionosphere with sufficient accuracy. The ionospheric response is supported by an additional study of the behaviour of the Total Electron Content (TEC), which response is similar to that of foF2.