PROPAGATION OF INTERNAL INERTIO-GRAVITY WAVE SPECTRA IN VERTICAL WIND SHEAR ENVIRONMENTS^*

The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper.From the hydrodynamic equation set in Boussinesq approximation,a spectral propagation equation ⅡGWs satisfy is derived,then the spectral correspondence in the upper atmosphere is numerically calculated,after a forced spectrum is given as a Van-Zandt one at the lower boundary.The results show that if ⅡGWs do not encounter the critical-layer absorption,then their spectral structure may be not changed significantly; otherwise it may be changed greatly,and a few of spectral components are filtered.Also the isotropy of the assumed VanZandt spectrum is distorted in upward-propagating process.That is the directional filtering effect of the atmospheric wind on the gravity wave spectrum.