Environmental Engineering Reference
In-Depth Information
Figure 7-19. Standard rates of atmospheric absorption.
[ANSI 1978]
Refraction Caused by Wind and Temperature Gradients
Refraction effects arising from the sound speed gradients caused by wind temperature
can cause nonuniform propagation as a function of azimuth angle around a source. A
simple illustration is shown in Figure 7-20 of
atmospheric refraction
(
i.e.
,
bending) of
sound rays, caused by a vertical wind-shear gradient over flat, homogeneous terrain around
an elevated point source. Note that in the downwind direction the wind gradient causes the
Figure 7-20. Effects of wind-induced refraction on acoustic rays radiating from an
elevated point source.
[Shepherd and Hubbard 1985]
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