On a Possible Generation Mechanism for Nonstationary Mountain Waves in the Atmosphere

Abstract

A three-dimensional theoretical model of the generation of mountain waves by a nonstationary wind flow is proposed in this paper. A mechanism of wave generation by scattering from orography of moving turbulent inhomogeneities of the wind flow velocity is examined. A calculation of the radiation level of mountain internal and infrasound waves and an investigation of their structure in the near-ground waveguide are carried out. A condition of the most effective generation of the mountain internal waves is found. The difference between propagation of a nonstationary and a well-known stationary wave is pointed out. Some experimental data are produced in the paper, which support a theoretical assumption about the existence of nonstationary mountain waves in the atmosphere and about the influence of these waves on the power spectrum and vertical structure of the pressure and wind velocity fluctuations in the boundary atmospheric layer and troposphere.