The Spectrum of High-Frequency Internal Waves in the Atmospheric Waveguide

Abstract

Abstract The vertical structure and power spectrum of the field of internal waves generated in the atmospheric waveguide by random vertical displacements were considered in this paper. The two-layered model of the atmosphere being used as a simple model of the waveguide takes into account the discrete spectrum of internal waves (both guided and vertically propagating). It is shown that these waves can produce the thin turbulent layers at certain heights, which are independent of random parameters of the source of internal waves. In the Eulerian frame of variables the wavenumber spectrum of internal waves, both three-dimensional and one-dimensional, tends asymptotically to a universal form at large wavenumbers. It is shown that the universal “tail” of the spectrum is formed by a strong mode's interaction caused by the advective nonlinearity and that the amplitude of the tail does not depend on the height above the ground. The characteristic vertical and horizontal wavenumbers of the three-dimensional Euler...