Intermittency of Kolmogorov and Coherent Turbulence in the Mountain Atmospheric Boundary Layer (Review)

— The review is devoted to the intermittency of atmospheric turbulence of different types (Kolmogorov and coherent) in the mountain boundary layer. The world scientific literature on the intermittency of turbulence is briefly reviewed for a better understanding of the place of each intermittency type. In view of the different interpretations of the coherent turbulence concept available in the literature, here, we supplement our earlier reviews of works on coherent turbulence and coherent structures, where the ways of generation of a coherent turbulence and its key properties were summarized and the differences and relationships between Kolmogorov and coherent turbulence were considered. The current concepts of the turbulence structure are discussed. Thus, we previously (2008–2019) showed that atmospheric turbulence could be considered an incoherent mixture of several coherent structures. A conjecture was suggested by Hopf in 1948 about the finite dimensionality of attractors in the phase space of solutions of the Navier–Stokes equations. In 1991 and 1992, a physical interpretation was suggested by Monin and Yaglom, where a turbulence structure was represented as a spatiotemporal chaos of a finite number of interacting coherent structures. The comparison between these representations has shown that our results actually prove the Hopf hypothesis in the interpretation by Monin and Yaglom, and that the turbulence “chaos” is largely deterministic. For the review, we use data on the intermittency of different turbulence types which are the result of long-term experimental studies of turbulence by acoustic and optical methods in high-mountain astronomical observatories. The lifetimes of Kolmogorov and coherent turbulence are derived from optical and meteorological measurements. The intermittency of turbulence is shown to characterize the local structure of turbulence above an observatory site, which has allowed us to formulate practical recommendations about the best observation conditions in astronomical observatories.