Formation of Turbulence at Astronomical Observatories in Southern Siberia and North Caucasus

Abstract

The main characteristics of the astroclimate (the structure of turbulent fields and conditions for their formation) are studied for several Russian astronomical observatories in southern Siberia and North Caucasus, including Sayan Solar, Baikal Astrophysical, Special Astrophysical, and Kolyvansky Ridge Observatories and the Center for Laser Atmosphere Sensing of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. The experimental results have been received from long-term astroclimate observations (expeditions in 2006–2017) with the use of small-size ultrasonic weather stations; and theoretical results, from the numerical solution of different boundary problems for the Navier–Stokes equations. The presence of regions with coherent (non-Kolmogorov) turbulence over the observatories has been ascertained, the formation of which is caused by the topography and the nonuniform heating of the underlying surface. Large-scale coherent vortex structures and coherent turbulence have been detected inside dome rooms. Numerical simulation allows us to analyze the influence of design features and temperature regimes of the telescope components and to test the telescope optical characteristics, including the minimization of the effects of external and under-dome turbulence. The paper includes the review of the history and evolution of the “coherent structure” and “coherent turbulence” concepts based on the world scientific literature and our own researches.