共查询到19条相似文献，搜索用时 171 毫秒
1.
海上风电是未来沿海各国海上能源开发的重点。我国海上风电正处于起步阶段,已建和规划中的风电场逐渐增多。国内对海上风电场环境影响研究,尤其是风机噪声对海洋生物的影响研究几近空白。文章总结了近年来国外海上风电场运营过程中水下噪声的基本概况,以及对海洋鱼类（游泳鱼类和底栖鱼类）、哺乳动物和底栖生物影响的研究成果。就我国未来海上风电场建设规划,提出海上风电场运营期风机噪声研究的不足及海洋生物听闽范围研究的缺乏,为我国制定海上风电项目环境影响评价规范提供科学参考,并指出水下噪声对我国海洋生物影响的研究方向。 相似文献
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海上风电场建设期风机打桩会产生高强度的水下噪声,研究水下冲击打桩噪声的监测方法、特性分析及对海洋生物的影响是非常重要的。采用自容式水下声音记录仪,多点同步测量了福建省兴化湾海上风电场二期工程建设期单次完整的水下冲击打桩噪声,从时频域特性进行了分析,并利用最小二乘法拟合得到了打桩声源级和声暴露级。结果表明：水下冲击打桩噪声是典型的低频、高强度的脉冲信号,单个脉冲持续时间约90~100 ms,峰值声源级约209.4±2 dB,声暴露级约197.7±2 dB;主要能量分布在50 Hz~1 kHz频段,750 m测量点的该频段声压级相比海洋环境背景噪声,提高了约40~50 dB。水下冲击打桩噪声频域能量分布与大黄鱼的听觉敏感频段相重叠,对大黄鱼影响程度和范围较大,实际工程应用中宜采用声暴露级作为评价指标。 相似文献
3.
近海风电场水下打桩辐射噪声特性测量分析 总被引：1，自引：0，他引：1
对滨海海上风电场一次完整的打桩过程不同水深处环境噪声进行监测和分析。结果表明:打桩过程水下辐射噪声脉冲信号,在所研究海域附近环境噪声级由原来打桩前的130 d B左右瞬间增加约20~50 d B,20~20 000 Hz频段,打桩噪声谱级高于工程前该海域背景环境噪声谱级约30~65 d B,100~1 000 Hz频率打桩辐射噪声谱级出现多个峰值,不同水深谱级最高峰值频率为200 Hz。根据打桩水下辐射噪声监测结果和浅海Marsh和Schulkin半经验公式,计算打桩辐射噪声声源级(距声源中心1 m处)为210.2 d B(参考声压1μPa)。为水下打桩辐射噪声的深入研究提供了基础数据,分析结果可供海洋环境和海洋生物保护研究参考。 相似文献
4.
由于适合水下目标辐射噪声测量的理想水域较少,因此测量试验大多在浅水有界水域开展,测量结果难免会受到试验现场界面反射波影响,导致测量的宽带声压级及各频率声压谱级产生偏差。利用虚源法对浅水有界水域下的声场模型进行了数值仿真,重点分析了导致传播损失异常的各项因素,然后基于脉冲声技术提出了一种水下目标浅水有界水域辐射噪声测量结果的修正方法,并进行了外场辐射噪声测量和传播损失异常值标定验证试验,最后对试验数据的测量结果进行了修正。 相似文献
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《中国海洋大学学报(自然科学版)》2015,(11)
基于简正波理论的波导不变量在声传播特性描述中已得到广泛应用,而当环境与距离无关或存在轻微扰动时,基于射线理论的声场特性可以用一个新的物理量—射线稳定性参数来描述。本文通过简正波干涉声场数值模拟,通过分析简正波相长干涉形成的能量包传播路径与射线传播路径相互关系,利用简正波水平干涉结构距离上的周期性与射线水平跨距相等的特点,采用简洁方式证明了射线稳定性参数与简正波波导不变量间的等价性,从而在射线和简正波理论中建立了一个新的联系。对远距离射线模型声传播仿真结果的分析表明,与射线传播时间相比,射线稳定性参数作为射线理论的一个新的参数,可有效用于描述声传播特性,并能够反映海洋环境变化,应用于海洋环境参数声学反演。 相似文献
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基于2006年Argo资料,计算两北太平洋海域0-1 500 m声速剖面.针对声速结构分类中分类数目难以客观选取和分类结果易陷入局部最优等问题,采用聚类中心动态调整的遗传编码方案和操作算子,充分利用模糊聚类与遗传算法的优势,运用改进的遗传聚类算法对西北太平洋声速剖面进行分类区划基于声场环境区划结果,运用Kraken简正波传播模型(Kraken Normal Wave Propagation Model)模拟典型声速结构的声传播损失场,借助表征声呐效能的优质因数(FO)M),分析典型声速结构的传播损失特征及其对声呐探测、水下潜器等活动的影响 相似文献
7.
文章简要介绍了浅海声传播损失的研究背景和基本理论方法。通过1/3倍频程滤波对浅海爆炸宽带信号的不同频段在浅海的传播损失情况进行了分析,描述了浅海环境对声传播损失的影响;同时在不知道先验信息的条件下,利用垂直阵声压数据成功地进行了简正波分离,并与理想条件下Kraken简正波模型计算出的结果进行了比较分析。 相似文献
8.
水面目标辐射噪声模拟技术是测试被动声呐系统、目标识别定向及水声软对抗的关键技术。通过对辐射噪声信号特性的描述及分析,建立了水面目标频域线谱及连续谱分量的数理仿真模型。针对水声信道影响因素,将Kraken简正波声场模型与信号本身特性有机结合。以1/3倍频程滤波带宽算法为基础,完成了对宽带FIR滤波器组的设计。采用现在应用广泛的GPU(Graphic Processing Unit)并行加速平台,实时实现了目标噪声模拟器整体架构,大大降低了系统硬件资源的消耗。通过对模拟器输出信号进行数理分析,证明了该模拟器能较好地实现水面目标的辐射噪声特性,具备良好的科研应用价值。 相似文献
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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. 相似文献
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为了解水下强噪声对大黄鱼的影响,结合行为学方法开展了3个年龄的大黄鱼声刺激实验．结果发现：3个年龄的大黄鱼在水中声压约10Pa时均能对声波发生条件反应,但是,它们的声波敏感频率和直接致死的声压阈值差异较大;1个月幼苗和8个月小鱼的声波敏感频率分别为800Hz和600Hz,直接致死的声压阈值约为40Pa和4kPa．13个月大鱼的声波敏感频率也在600Hz,但当声压达到4kPa时,鱼群受惊吓明显,且未能直接致死．另外,这些曾经暴露在强声波中的各年龄段的大黄鱼在随后48h里较多出现相继死亡的现象．表明这些长时间暴露在水下噪声中的大黄鱼可能会因累积效应引起行为模式改变和间接致死等慢性危害． 相似文献
13.
基于潜标测量的海洋环境噪声谱特性分析 总被引：3，自引：1，他引：2
利用海洋环境噪声测量潜标系统对南海典型海域开展了为期3个月的海洋环境噪声测量,16通道海洋环境噪声测量系统每小时测量两分钟噪声信号。数据处理结果表明,800~5 000Hz范围内,噪声谱与风速相关性最好,且风速越大相关性越好,噪声谱与风速的相关性好于与浪高的相关性。风关噪声谱级在海水中部基本不随接收深度发生变化,但由于测量水听器阵长度未能覆盖整个水深,因此未给出海面和海底处谱级变化规律。在400Hz以上的高频段整个风速范围内噪声谱级都随风速发生变化,且噪声谱级与对数风速具有很好的线性关系。 相似文献
14.
The correlation of ambient noise with wind speed, and the depth dependence of ambient noise are both investigated, where the ocean noise data were recorded by a vertical line array in the northern South China Sea. It is shown that the correlation coefficients increase with increasing hydrophone depth during typhoon periods when the frequency ≥ 250 Hz, which opposes the generally accepted knowledge that the correlation coefficients of noise level and wind speed decrease with increasing depth during non-typhoon periods. Particularly at frequencies of 250 Hz, 315 Hz and 400 Hz, the correlation coefficients increase by more than 0.05 at depths ranging from 155 m to 875 m. At the three frequencies, the average noise levels also increase with increasing depth during typhoon periods. It is suggested that these differences are attributed to the wind-generated noise in shallow waters and the effect of "downslope enhancement" to sound propagation. During typhoon periods, the surf breaking and surf beat upon the shores and reefs are strengthened, and the source levels are increased. The wind-generated noise in shallow waters interacts with the downslope sea floor, with the noise-depth distribution changed by a "downslope enhancement" effect promoting noise propagation. 相似文献
15.
风通过影响海洋表面从而产生200 Hz以上的深海环境噪声,但有研究指出,通过风生表面波之间的非线性相互作用产生的驻波,能够与海床共振构成海底微震,从而产生10 Hz以下的噪声。针对这一新型风生噪声机制,本研究对威克岛海域10 Hz以下的极低频噪声进行了分析。比较了不同频率下海洋环境噪声功率谱级与风速的相关性,并讨论了风速和风向对设立在威克岛南北部二组水听器三联体信号的影响,结果表明2 Hz处的海洋环境噪声级与风速相关性最好,而风速和风向变化越剧烈海洋环境极低频噪声与风速风向的相关性越好。 相似文献
16.
Mapping wind with high-frequency(HF) radar is still a challenge. The existing second-order spectrum based wind speed extraction method has the problems of short detection distances and low angular resolution for broad-beam HF radar. To solve these problems, we turn to the first-order Bragg spectrum power and propose a space recursion method to map surface wind. One month of radar and buoy data are processed to build a wind spreading function model and a first-order spectrum power model describing the relationship between the maximum of first-order spectrum power and wind speed in different sea states. Based on the theoretical propagation attenuation model, the propagation attenuation is calculated approximately by the wind speed in the previous range cell to compensate for the first-order spectrum in the current range-azimuth cell. By using the compensated first-order spectrum, the final wind speed is extracted in each cell. The first-order spectrum and wind spreading function models are tested using one month of buoy data, which illustrates the applicability of the two models. The final wind vector map demonstrates the potential of the method. 相似文献
17.
Zhaohui Peng Ji-Xun Zhou Dahl P.H. Renhe Zhang 《Oceanic Engineering, IEEE Journal of》2004,29(4):1038-1045
As a part of the Asian Seas International Acoustic Experiment (ASIAEX) in the East China Sea, sound propagation signals from wideband explosive sources were measured using a 32-element vertical line array. Measurements were made as a function of range in two perpendicular tracks. Sea-bed geoacoustic parameters based on a fluid half-space geoacoustic model (sound speed, density, and attenuation) are inverted from the sound propagation in the frequency range 100-500 Hz. The sea-bed sound speed and density were first derived from mode arrival time differences which were obtained using a spatial mode filtering technique. Sea-bed acoustic attenuation was subsequently estimated by comparing measured transmission loss with model results. 相似文献
18.
The Ieodo Ocean Research Station(IORS) is an integrated meteorological and oceanographic observation base which was constructed
on the Ieodo underwater rock located at a distance of about 150 km to the south-west of the Mara-do, the southernmost island
in Korea. The underwater ambient noise level observed at the IORS was similar to the results of the shallow water surrounding
the Korean Peninsula (Choi et al. 2003) and was higher than that of deep ocean (Wenz 1962). The wind dependence of ambient
noise was dominant at frequencies of a few kHz. The surface current dependence of ambient noise showed good correlation with
the ambient noise in the frequency of 10 kHz. Especially, the shrimp sound was estimated through investigations of waveform
and spectrum and its main acoustic energy was about 40 dB larger than ambient noise level at 5 kHz. 相似文献
19.
Underwater sounds near a fuel receiving facility in western Hong Kong: relevance to dolphins 总被引：1，自引：0，他引：1
Western Hong Kong is home to two species of marine mammals: Indo-Pacific humpbacked dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides). Both are threatened in many parts of their range in southeast Asia [for example, International Biological Research Institute Reports 9 (1997), 41; Asian Marine Biology 14 (1997) 111]. In 1998, when the new Hong Kong International Airport opened in western Hong Kong, small tankers (about 100 m long, cargo capacity about 6300 metric tons) began delivering fuel to the Aviation Fuel Receiving Facility (AFRF) just off Sha Chau Island, north of the airport. Calibrated sound recordings were taken over a 4-day period from a quiet, anchored boat at distances 80-2000 m from aviation fuel delivery activities at the AFRF. From the recordings, 143 sections were selected for analysis. Narrowband spectral densities on the sound pressures were computed, and one-third octave band levels were derived for center frequencies from 10 to 16,000 Hz. Broadband levels, viz. 10-20,000 Hz. were also computed. The results showed that the Sha Chau area is normally noisy underwater, with the lowest broadband levels measured corresponding to those expected during a storm at sea (sea state 6). This background noise is believed to come largely from heavy vessel traffic in the Urmston Road to the north and east of Sha Chau and from vessels in the Pearl River Estuary to the West. The sound levels from the AFRF tankers are comparable to the levels measured from similar- and smaller-sized supply vessels supporting offshore oil exploration. The strongest sounds recorded were from a tanker leaving the AFRF at distance 100 m from the hydrophone, for which the one-third octave band level at 100 Hz was 141 dB re 1 microPa (spectrum level 127 dB re 1 microPa2/Hz) and the 10-20,000 Hz broadband level was 146 dB. At distances of 100 m or more and frequencies above 300 Hz, the one-third octave band levels were less than 130 dB (spectrum level 111 dB re 1 microPa2/Hz) and decreased with increasing frequency and distance. At distances greater than about 500 m, AFRF-associated sounds were negligible, masked by the generally high noise level of the area and attenuated by poor transmission in the very shallow water (<10 m). Because it is believed that humpbacked dolphins and finless porpoises are not very sensitive to sounds below 300 Hz, the Airport Authority Hong Kong (AA) stipulated that dedicated terminal vessels not radiate underwater sounds at spectrum levels greater than 110 dB re 1 microPa2/Hz at frequencies above 300 Hz and distances greater than 300 m. The spectrum levels at 300 Hz and higher frequencies of sounds from the tankers arriving, departing, or off-loading at AFRF were less than 110 dB re 1 microPa2/Hz even at distances of 200 m or less. The AA stipulation was met. However, it is presently unknown whether the generally strong noise levels of western Hong Kong inhibit acoustically based feeding and communication, or result in increased stress or permanent shifts in hearing thresholds. 相似文献