This article examines the sound generated when the wind interacts with vegetation. A wind field model has been coupled to a new method for predicting sound from vegetation. This includes predictions from coniferous, deciduous and leafless trees. The proposed prediction method and an earlier model have been compared with measurements which show improved agreement, in particular in the region below 1 kHz. Comparisons between five measurement sites and predictions show satisfactory agreement for wind speeds up to 8.5 m/s. Fluctuations in the vegetation noise level due to wind turbulence can also be accurately estimated.

This paper describes a semi-empiric model and measurements of air-borne sound generated by breaking sea waves. Measurements have been performed at the Baltic Sea. Shores with different slopes and sediment types have been investigated. Results showed that the sound pressure level increased from 60 dB at 0.4 m wave height to 78 dB at 2.0 m wave height. The 1/3 octave spectrum was dependent on the surf type. A scaling model based on the dissipated wave power and a surf similarity parameter is proposed and compared to measurements. The predictions show satisfactory agreement to the measurements. (C) 2010 Acoustical Society of America. [DOI: 10.1121/1.3327815]

This paper describes methodology and results from a model-based analysis of data on sound transmission from controlled sound sources at sea to a 10-km distant shore. The data consist of registrations of sound transmission loss together with concurrently collected atmospheric data at the source and receiver locations. The purpose of the analysis is to assess the accuracy of methods for transmission loss prediction in which detailed data on the local geography and atmospheric conditions are used for computation of the sound field. The results indicate that such sound propagation predictions are accurate and reproduce observed variations in the sound level as function of time in a realistic way. The results further illustrate that the atmospheric model must include a description of turbulence effects to ensure predicted noise levels to remain realistically high during periods of sound shadow. (C) 2009 Acoustical Society of America. [DOI: 10.1121/1.3238236]

Wind turbine (WT) noise may cause annoyance, especially in relatively quiet areas with low ambient levels. As a compliment to conventional noise control at the source, addition of wanted sounds may reduce the loudness of WT noise by auditory masking. In order to test this, two masking experiments were conducted with two WT noises as target sounds and three natural sounds as maskers (wind in coniferous or deciduous trees and sea waves). In the first experiment, 30 listeners determined the detection thresholds of WT noise in the presence of the natural sounds using a threshold tracking method. In the second experiment, the same group of listeners matched the loudness of partially masked WT noise with the loudness of unmasked WT noise. The results showed that detection thresholds for WT-noise in the presence of natural sounds from trees and sea waves were around -8 to -12 dB S/N-ratio. Furthermore, a reduction of perceived loudness of WT-noise was found for S/N-ratios up to 2 dB. These results were compared with predictions from two models of partial masking (steady and time variant). In general, empirically determined detection thresholds and partial loudness matches were higher than predictions from the two models.