Tkachev I.D., Vasilyev R.V., Belousova E.P. «Cluster analysis of lightning discharges: based on Vereya-MR network data» Солнечно-земная физика, 7, № 4, с. 85-92 (2021)

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the LF-VLF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Tolstikov M.V., Ratovsky K.G., Medvedeva I.V., Khabituev D.S. «Estimated influence of stratospheric activity on the ionosphere according to measurements with ISTP SB RAS tools» Солнечно-земная физика, 7, № 4, с. 79-84 (2021)

We present the results of a comprehensive study of the manifestation of wave activity with periods of internal gravity waves (IGW) in various regions of the atmosphere: in the stratosphere, upper mesosphere, and in the F2-region of the ionosphere. The study is based on radiophysical and spectrometric measurements made with tools of the Institute of Solar-Terrestrial Physics (ISTP) SB RAS and the Era-Interim reanalysis data. The correlation coefficient with time shift between ionospheric and stratospheric activity for the annual interval varies in the range from 0.45 to 0.54, and for the 27-day interval it reaches the levels 0.4–0.8 in seventy percent of the cases. Thirty percent of correlation coefficients less than 0.4 can be explained by the influence of neutral wind, geomagnetic activity, and nonstratospheric IGW sources. Comparison between stratospheric activity and variations in characteristics of traveling ionospheric disturbances (TID) has shown that a ∼15 day shift in stratospheric activity results in a fairly high correlation between stratospheric activity and disturbance of IGW characteristics (∼0.6). The delay of about 15 days can be attributed to the delay in the temperature variations at heights of the lower thermosphere relative to the temperature variations at the altitude pressure level of 1 hPa. Comparative analysis of variations in mesospheric and ionospheric activity has revealed time intervals when their behavior is consistent.