  A problem of finding the linear theory satisfaction limits in propagation of
the internal gravity waves is considered. It is evident that internal gravity
waves excitation, propagation in actual practice is highly nonlinear
phenomenon. However with some reasonable assumptions it is possible to
linearize equations of internal waves generation and propagation. It is shown
that in interesting for us wavelength range we can use linear approximation
during study of internal gravity waves dynamics. Similarly it is easy to
evaluate also influence of other corrections to the linear theory of internal
gravity waves generation and propagation, and the obtained results indicate
adequacy and supportability of linear model wave dynamics.
