Characteristics of underwater ambient noise at a proposed tidal energy site in puget sound
Characteristics of underwater ambient noise at a proposed tidal energy site in puget sound
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普吉特湾拟议潮汐能地点水下环境噪声的特征
DOI：
10.1109/oceans.2010.5664380
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
B. Polagye
中科院分区：
文献类型：
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作者：
Christopher Bassett;Jim Thomson;B. Polagye
在美国华盛顿州金钟湾的一个潜在潮汐能站点提供了为期一年的环境水声数据，该站点的最大洋流超过3米/S。该站点位于大约60米深的地方，靠近航道、当地的渡轮航线和许多鲸目动物的中转区。一个重要的发现是，总声压级的统计分布取决于现场的潮流。伪声、海床上的鹅卵石移动，以及设备上的力引起的振动都是可能的解释。被称为伪声的非传播湍流压力波动可以掩盖环境噪声，特别是在适合潮汐能开发的高能环境中。一种统计方法确定三分之一倍频程频带声压级的平均值和标准差的变化在统计上具有显著意义的时段，从而暗示存在伪声污染。对于每一次部署，深度平均潮流大于1m/S的记录被发现受到污染，并且只有低于这一阈值的记录才被用于随后的环境噪声分析。所有录音的平均总声压级(0.156-30μ)为117分贝Re 1 KHZ帕。总声压级超过100dBre 1μPa99%的时间和超过135dBRe 1μPa4%的时间。商业航运和渡轮交通被发现是该地点环境噪声水平的最主要贡献者，其次是雨、风和海洋哺乳动物的发声。来自AIS(自动识别系统)接收器的后处理数据用于在每次记录期间确定船只的位置。参考368条由美国航空航天局数据获得的渡口到现场距离的个人记录，估计渡口在1m处的源能级为179±4dBRe 1μpa，对数扩展损耗系数为18。
Ambient underwater acoustics data are presented for one year at a potential tidal energy site in Admiralty Inlet, WA (USA) with maximum currents exceeding 3 m/s. The site, at a depth of approximately 60 meters, is located near shipping lanes, a local ferry route, and a transit area for many cetacean species. A key finding is that the statistical distribution of total sound pressure levels are dependent on tidal currents at the site. Pseudosound, cobbles shifting on the sea bed, and vibrations induced by forces on the equipment are possible explanations. Non-propagating turbulent pressure fluctuations, termed pseudosound, can mask ambient noise, especially in highly energetic environments suitable for tidal energy development. A statistical method identifies periods during which changes in the mean and standard deviation of the one-third octave band sound pressure levels are statistically significant and thus suggestive of pseudosound contamination. For each deployment, recordings with depth averaged tidal currents greater than 1 m/s are found to be contaminated, and only recordings with currents below this threshold are used in the subsequent ambient noise analysis. Mean total sound pressure levels (0.156 - 30 kHz) over all recordings are 117 dB re 1μPa. Total sound pressure levels exceed 100 dB re 1μPa 99% of the time and exceed 135 dB re 1μPa 4% of the time. Commercial shipping and ferry traffic are found to be the most significant contributors to ambient noise levels at the site, with secondary contributions from rain, wind, and marine mammal vocalizations. Post-processed data from an AIS (Automatic Identification System) receiver is used to determine the location of ships during each recording. Referencing 368 individual recordings with the distance between the ferry and the site obtained from AIS data, the source level of the ferry is estimated to be 179 ± 4 dB re 1μPa at 1m with a logarithmic spreading loss coefficient of 18.