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The paper analyzes meteorological and optical characteristics of the atmosphere at the Sayan Solar Observatory (SSO) and the future 3 m Large Solar Telescope (LST-3). We examine spatial features of changes in astroclimatic characteristics for the Sayan Solar Observatory and Baikal Astrophysical Observatory (BAO). We have obtained a vertical profile of the structural characteristic of air refractive index fluctuations for a low intensity optical turbulence along the line of sight. This profile is an important result because it will allow us to adjust the adaptive optics system of LST-3 to the best astroclimatic conditions when the correction efficiency is maximal. In order to analyze vertical profiles of optical turbulence characteristics and to assess the contribution of individual atmospheric layers to the isoplanatic angle for a minimum level of total turbulence, we give recommendations for the design of multi-conjugated adaptive optics in general and for LST-3 in particular.

The subject of this study is oscillations in the lower atmosphere in coronal-hole regions, where the conditions are favorable for propagation between the atmospheric layers. Based on spectroscopic observations in photospheric and chromospheric lines, we analyzed the features of the oscillations that show signs of propagation between the layers of the solar atmosphere. Using the cross-spectrum wavelet algorithm, we found that both chromospheric and photospheric signals under coronal holes share a range of significant oscillations with periods around five minutes, while the signals outside coronal holes show no mutual oscillations in the photosphere and chromosphere. The phase shift between the layers indicates a predominantly upward propagation with partial presence of standing waves. We have also tested the assumption that the torsional Alfvén waves propagating in the corona originate in the lower atmosphere. However, the observed line-width oscillations, although similar in period to the Alfvén waves observed earlier in the corona of open-field regions, seem to be associated with other magnetohydrodynamic (MHD) modes. If we assume that the oscillations that we observed are related to Alfvén waves, then perhaps this is only through the mechanisms of the slow-MHD-wave transformation.

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