船舶噪声对浅海海洋环境噪声空间相关的影响

Spatial correlation of ambient noise affected by ship-radiated noise in shallow sea

通过对2001年亚洲海国际声学实验(ASIAEX)得到的海洋环境噪声数据进行处理,计算了噪声场空间相关系数、功率谱密度和垂直指向性,分别研究了受到远距离和近距离船舶辐射噪声影响的海洋环境噪声空间相关性.结果表明:船舶距离较远(>10 km)时其辐射噪声会导致500 Hz以下的海洋环境噪声的空间相关性提高,而对500 Hz以上噪声的空间相关性没有影响;船舶距离较近(≤10 km)时,船舶辐射噪声会导致500 Hz以下的海洋环境噪声相关系数振荡变化,噪声空间相关性曲线在噪声信号声程差相差四分之一波长时出现第一个零点,对500 Hz以上的海洋环境噪声则会引起噪声能量升高,噪声的空间相关性也相对提高.基于现有理论,分别讨论了远距离船舶和近距离船舶产生的噪声场声学特性,对两种噪声场的海洋环境噪声空间相关性进行了合理的解释.

Based on the processed data of the ambient noise measured with ASIEX 2001 in the South China Sea,the noise power spectral density and vertical directivity are calculated and the spatial correlation of ambient noise in shallow sea influenced by ship-radiated noise is studied. Results show that when the ships are far away from the receivers( > 10 km),the ship-radiated noise increases the spatial correlation of the environment noise below 500 Hz and have no effect on the spatial correlation of the environment noise above 500 Hz. When the ships are near the receivers( ≤10 km),the ship-radiated noise causes the oscillation of spatial correlation of the environment noise below 500 Hz. The noise spatial correlation curve shows the first zero point when the acoustic path of the noise signal differs by a quarter wavelength,The energy of the noise increases when the environment noise is below 500 Hz.Based on the existing theory,this paper discusses the acoustic characteristics of the noise field produced by ships far away from receivers and noise field in close range,and makes a reasonable explanation of the spatial correlation of two ambient noise fields.