Long-Term Variations in the Parameters of the Middle and Upper Atmosphere and Ionosphere (Review)

The article reviews the main publications from the last eight years on long-term trends in the parameters of the middle atmosphere, thermosphere, and ionosphere. It is shown that the negative temperature trends in the middle atmosphere have been reliably established based on observations by various methods. An analysis of satellite orbits in the thermosphere showed negative density trends at heights of ~400 km. Unexpectedly high negative trends in ion temperature Ti above ~220 km obtained with the incoherent-scatter method. The same measurements high positive trends in Ti at the heights of the F1 layer. There are discrepancies in the estimates of the absolute value of the negative trends in the critical frequency and height of the F2 layer; however, these trends are high in the opinion of the authors.