BOOK OF ABSTRACTS AND CONTRIBUTED PAPERS: International scientific conference Meeting on Operational and Research Capabilities for Better Understanding Solar-Terrestrial Interactions ,
Pages: 84-86,
https://doi.org/10.69646/aob250929
International scientific conference Meeting on Operational and Research Capabilities for Better Understanding Solar-Terrestrial Interactions
Published by: Scientific Society Isaac Newton

Variations in solar activities ar e evident through solar cycles. These cycles can occur on millennial, centennial, and decadal timescales, although solar activity also changes on yearly (seasonal), monthly, and daily scales. Milutin Milankovi ć, in his well -known cycles, described the millennial -scale changes in the Sun –Earth relationship and laid the foundations of mathematical climatology. Valentina Zharkova proposed that the centennial solar cycle may result from the interference of two magne tic waves with similar but not identical frequencies. According to her finding s, the Sun has entered a modern Grand Solar Minimum, which is expected to lead to a significant reduction in the solar magnetic field. This article focuses on decadal solar activity, specifically the 11 -year solar cycle. Changes in this cycle affect temper ature and atmospheric circulation, thereby influencing the conditions for the propagation and reflection of gravity waves (GWs) in the Earth’s middle atmosphere. These effects are most pronounced in the stratosphere, where variations in solar UV radiation can increase temperatures by up to 3 K and alter ozone concentration by approximately 2%. Additionally, during extreme solar minima, the lower thermosphere becomes relatively cold, with temperatures around 500 K. In contrast, during periods of high solar a ctivity, temperatures in the thermosphere can reach up to 2000 K. In this study, we examined the characteristics and propagation of gravity waves under these varying conditions.