Sound propagation in the atmosphere involves many wave phenomena. Some
of them, e.g., scattering on turbulence, and ground effect, interact
with each other. Using the equation of state for relaxation in a binar
y mixture of gases, such as oxygen and water vapor, it is shown that t
he interaction between the ground effect and air absorption can be neg
lected. (C) 1997 Acoustical Society of America.