Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN) has been conducting regular observations of the parameters of the lower atmosphere, ionosphere, and variations in the Earth’s magnetic field. The base of the measuring equipment, located in Ulyanovka village, Kaliningrad region (54° N, 20° E) consists of ionosonde for the vertical sounding of the ionosphere; two-frequency GPS/GLONASS receivers, which are used to determine the total electron content in the ionosphere; magnetic variation stations for the continuous recording of variations of the three components of the Earth’s magnetic field vector and calculating the local K-index; and a weather station. The simultaneous observations of variations in the magnetic field, as well as the ionospheric and meteorological parameters in the same observatory, offer a wide range of opportunities to study the atmospheric-ionospheric relations. This article provides a brief description of all the tools, provides a method for transmitting and storing the time series of measured parameters, and also presents examples of using these data for various geophysical studies.

The paper presents the results of observations of the sporadic Es layer during the period of meteorological disturbances in Kaliningrad in October 2017 and 2018 under quiet geomagnetic conditions. During the meteorological storms (October 29–30, 2017 and October 23–24, 2018), significant changes occurred in the dynamics of the Es-layer critical frequency. Observations of atmospheric and ionospheric disturbances in the Kaliningrad region show that the delay between the ionospheric response and the moment of maximum disturbances in atmospheric parameters is about 3 hours. These phenomena at the heights of the E-region might have been caused by propagation of acoustic-gravity waves generated by convective processes in the lower atmosphere during periods of a meteorological storm. Intensification of turbulent processes in the lower thermosphere leads to an increase in the atmospheric density and, accordingly, to higher recombination rates. This leads to a rapid decrease in the concentration of ions and, consequently, to a decrease in the critical frequency of the sporadic layer below the sensitivity threshold of ionosondes.

The maximum electron density of the F2 layer N(m)F2 relative to the solar activity level is studied. The optimal period for averaging the solar activity index F-10.7 is found, which gives on average the lowest error and the highest correlation coefficient (in space and in time) for describing the linear dependence of N(m)F2 vs. F-10.7. This result depends substantially on the duration of N(m)F2 data storage selected.

The study presents the results of the analysis of the F2-layer critical frequency variations obtained for the winter periods of 2008–2010, during which sudden stratospheric warmings were observed. The data were obtained at Kaliningrad ionospheric station (54.6° N, 20° E) with the Parus digital ionosonde in standard sounding mode. The mean daily foF2 values were used in the analysis. The results of spectral analysis based on continuous wavelet transform showed that, during all of the warmings that occurred in 2008–2010, the foF2 time variations demonstrated the presence of wave processes with periods of approximately 5−6 days, as well as more extended processes with periods of ~10−13 and 23−30 days. These periods coincide with the characteristic periods of planetary waves observed in the mesosphere during sudden stratospheric warmings, while the 13- and 30-day periods can be conditioned by the influence of the Sun.

The results of studies of the dependence of the daily electron concentration at maximum of the F2 ionospheric layer in January 2008–2015 on the solar and geomagnetic activity are presented. The solar radio emission flux density indices F10.7 and geomagnetic activity indices A p were averaged over 27 days, and 〈F10.7〉27 and 〈A p 〉27, respectively, were obtained. Based on the data of three stations, 27-day median (with the middle of January 15) daily N m F2 variations were obtained for 2008–2015. Based on these data, the following paradox was discovered: in January 2014, when the values of the solar activity index F10.7 were larger than in 2015, the dailyN m F2 values were smaller. Averaging over four hours of local daytime (10:00–14:00 LT) gave the daily average January 〈N m F2〉 values for each selected station for each year. To solve this paradox, a double linear regression of 〈N m F2〉 on 〈F10.7〉27 and 〈A p 〉27 was constructed. Due to this, it was concluded that the contribution of geomagnetic activity to daily January 〈N m F2〉 values is positive. A comparison of the mean square errors of the linear and double linear regressions for 〈F10.7〉27 and 〈F10.7〉81 showed that the use of 〈F10.7〉27 led to smaller errors than the use of 〈F10.7〉81.