Features of Long-Period Trends of Main Parameters F2 of the Ionosphere Area in Tomsk

The report discusses the features of the long-term trends of the main parameters of the F2 region of the ionosphere in the city of Tomsk. The trends of the critical frequency, depending on the solar activity cycle, have both a positive and a negative trend, the latter predominantly. In this case, the trends of the critical frequency and the effective altitude F2 of the ionosphere region depend, in addition to both the level of solar activity, and the time of day and season of the year.