Investigating uncertain geometries effect on sound propagation in a homogeneous and non-moving atmosphere over an impedance ground

Predicting outdoor sound in uncertain conditions is a difficult task and there are limited data which enable us to relate accurately the variations in the conditions in the propagation path with the fluctuations in the received acoustical signal. This paper investigates, though numerical simulations, the effect of uncertainties on sound propagation in a homogeneous atmosphere over an impedance ground. A simple Monte Carlo method is used to understand the effect of uncertainties in the source and receiver positions on the excess attenuation. The ratio of source/receiver height to the horizontal source/receiver separation is found to influence strongly the statistical distribution of the resultant excess attenuation spectrum. Impedance ground and level of uncertainty are found to be influential only for specific statistics while all samples were found to violate normality. These findings help to increase understanding of the role of uncertainties in outdoor sound propagation, accuracy of source characterization based on parameter inversion and at lower computational costs.