  In this paper, we concerned with the propagation of sound waves through
stratified media. Transport equation of nonlinear geometric optics in media
with mixed nonlinearity, in the case of spatially varying density and entropy
fields, is derived; this equation contains a cubic nonlinear term in addition
to the quadratic nonlinearity. We consider an atmosphere where thermodynamic
quantities depend on the height only. Effects of real gas parameters, density,
and entropy attenuation parameters on the breakdown of the solution are
investigated numerically.
