Turbulence in the free atmospheres of Earth, Mars, and Venus: A review

Turbulence is of high importance in the atmospheres of terrestrial planets. It enhances transport processes and the dissipation of the energy of motion and affects the thermal regime, dynamics, and composition of atmospheres. In particular, turbulence is responsible for the presence of the homosphere, i.e., the region whose composition and molar mass do not depend on height, and of the heterosphere, where the lighter the atmospheric components are the faster their relative concentrations increase with height. The atmospheric planetary boundary layer turbulence essentially influences weather and climate and is examined in many experimental and theoretic studies. The turbulence pattern in the free atmosphere is much more complicated and much less studied, although the information related to free atmosphere turbulence is important for the solution of such urgent problems as the security of air flights, the anthropogenic effects on the ozonosphere, and many others. The complex character of the turbulence pattern within the free atmosphere is associated with the presence of several sources of its energy, which are randomly distributed in time and space. Hence, many simplifications are usually adopted when interpreting experiments and performing computations using theoretical models. Therefore, the comparison and refinement of different data are constantly needed. The present review summarizes the experimental and theoretical data on free atmosphere turbulence on Earth, Mars, and Venus, the information related to its influence on the atmospheric structure and dynamics, as well as the problems of its description.