## 3 Conclusions
According to the researchers, these distributions confirmed that the best transparency (among the considered sites in Russian territory) was found at the Terskol Peak Observatory. The results presented in these works allow us to say that optical transparency conditions are somewhat better in the Sayan Mountains (Khulugaisha Peak) and in Altai (Tashanta) (for comparable altitudes above sea level) [14; 15]. For the first time, we carried out studies of the structure of atmospheric flows in individual regions of Russia using the mesoscale WRF model, with the aim of assessing and short-term forecasting atmospheric characteristics, including mesoscale atmospheric turbulence and small-scale (parameterized) turbulence. The modeling of vertical profiles of wind speed, temperature and air humidity was performed up to a height of 25 km within a wide region above the Sayan Solar Observatory and the Baikal Astrophysical Observatory. We successfully performed a series of experiments to reconstruct the wind speed field at a horizontal resolution of 500 m in the internal domain of the WRF model within this macroregion. Based on the modeling results, it is shown that the boundaries of Lake Baikal and the Angara River valley are clearly visible in the wind speed field. This demonstrates the correctness of the modeling of the temperature, humidity and wind fields. Using the WRF model for the first time in the Baikal Lake Basin, mesoscale vortex structures with anticyclonic air flows during the daytime were discovered in the atmospheric boundary layer, affecting the quality of astronomical images. Analysis of the horizontal energy spectra showed that the characteristic scales of this mesoscale vortex structure, the center of which is formed north of the BAO, vary from 10 to 20 km. The modeling results show that upward air movements in the lower atmosphere are suppressed both above the cold surface of Lake Baikal and within these mesoscale eddy structures. It was shown for the first time that the turbulence over the BAO significantly depends on the orography and characteristics of mesoscale atmospheric disturbances (mesoscale eddies and jets). The best reproducibility of local air circulation during the day corresponds to the YSU parameterization scheme. Using the WRF model, vertical profiles of wind speed and air temperature over the BAO under clear-sky conditions were obtained and detailed. Using the vertical profiles of these characteristics, vertical profiles of optical turbulence were reconstructed. The first attempts at short-term forecasting showed a good reproduction of the changes in surface atmospheric characteristics (primarily wind speed), but significant deviations in amplitude were often observed. In addition to wind speed, the WRF model was able to adequately describe the time variations in the characteristics of the integral turbulence energy in a layer up to 20 km thick (with a correlation coefficient of 0.9), but significantly underestimated the amplitude of the optical turbulence integral along the height. The difference in amplitude is associated with a rather rough relief model and the applicability conditions of physical processes' parameterization schemes. A special system for measuring optical distortions and estimating the vertical profiles of optical turbulence up to an altitude of about 20 km was proposed. This system was implemented on the New Vacuum Solar Telescope (NVST). By processing the measurement data obtained from the New Vacuum Solar Telescope, it is shown that the SLODAR method's accuracy in determining vertical profiles is approximately 93%. The accuracy of the S-DIMM+ method is slightly lower, at 87%. The S-DIMM+-derived values of optical turbulence strength are lower than the strengths obtained using the SLODAR method. The turbulent layer at heights near the tropopause is not distinguished. Investigation, writing--review and editing: A.Y.S. ; methodology and editing: P.G.K. All authors have read and agreed to the published version of the manuscript.