Comparative Measurements of Atmospheric Turbulence Parameters by Optical Methods

— Different methods for measuring random wavefront tilts are considered. Possibilities of measuring the Fried parameter by the differential method in problems of turbulence sensing and adaptive optics are determined. Comparative measurements of the turbulence strength along a horizontal path were carried out by two optical methods: (1) with a differential turbulence meter and (2) passive method based on image jitter measurements with a high-speed digital video camera mounted on a small astronomical telescope and real-time processing algorithms. Possible differences in the measurement results are discussed. Patterns of the evolution of the convective motion of a medium inside a volume in terms of the vector velocity field and scalar temperature and pressure fields are derived on the basis of numerical solution of the set of Navier–Stokes equations. Ways of improving a wavefront sensor for high-precision phase measurements in both Kolmogorov and non-Kolmogorov turbulence are suggested.