岛礁区域斜坡地形对深海环境噪声级深度分布的影响

The effect of slope of island reef on the deep sea ambient noise

考虑岛礁区域斜坡地形的影响,从理论上分析了南海深海区域噪声级随深度增加而变大的现象。南海北部深海区域环境噪声测量实验表明:大部分时间内噪声谱级随深度变化较小(160～800 m),但是在一些时间里,噪声谱级会出现随深度增加而变大的现象。考虑南海岛礁区域斜坡地形对声传播的影响,建立了南海深海区域的环境噪声模型,当航船经过岛礁附近时,航船噪声由于岛礁附近斜坡地形的作用进入深海声道,使远距离噪声谱级随深度增加而变大。利用模型计算噪声谱级随深度的分布,结果与实验数据符合较好。验证了南海深海区域噪声在岛礁斜坡地形影响下的复杂的变化特性。

Considering the effect of the slope of reef area, the phenomenon that the noise level in the deep sea area of the South China Sea becomes bigger with depth increasing is analyzed theoretically. The experiment on ambient noise in the deep sea area of the northern South China Sea shows that the noise spectrum level changes little with depth(160 m to 800 m) for most of the time, but at some time, the phenomenon that the noise spectrum level will increase with depth increasing would arise. Considering the effect of topography on sound propagation in the South China Sea, the ambient noise model of deep sea area in the South China Sea is built. When the ship passes the sea around the reef or island, the ship noise spreads into the deep sea sound channel due to the terrain near the reef or island, the distant noise spectrum level increases with depth increasing. The distribution of noise spectrum level with depth can be computed by using the noise model, and it has good agreement with the experimental data. So the variation characteristics of deep sea noise affected by the slope of island reef in the South China Sea are verified.