K. Attenborough et Km. Li, GROUND EFFECT FOR A-WEIGHTED NOISE IN THE PRESENCE OF TURBULENCE AND REFRACTION, The Journal of the Acoustical Society of America, 102(2), 1997, pp. 1013-1022
Closed-form approximations, of ground effect for continuous A-weighted
noise from a point source near to finite impedance ground, obtained b
y Li et al. [J. Acoust. Sec. Am. 88, 1170-1172 (1990)] and Makarewicz
[J. Acoust. Sec. Am. 82, 1706-1711 (1987); 88, 1172-1175 (1990)], are
extended to take account of more general models for ground impedance i
ncluding revised variable-porosity, thin-layer, and rough porous groun
d where the roughness is small compared with incident wavelengths. The
influences of both turbulence and weak atmospheric refraction within
the illuminated zone are included. Approximate relationships between o
ptimum ground effect for A-weighted noise, ground parameters, source s
pectrum, source height, and receiver height are predicted and explored
. For low source heights and noise sources with A-weighted spectra wit
h low peak frequencies, it is possible to indicate ground surface para
meters that will give significantly higher excess attenuation than tho
se typical of grass-covered ground. It is predicted that, in the illum
inated zone, the optimum ground effect parameters are fairly robust to
weak refraction effects. (C) 1997 Acoustical Society of America.