Study of Sound Characteristics of Rain Noise at Sea

海上降雨引起的噪声信号（简称降雨噪声）是海洋环境噪声背景场的一个重要干扰源，会极大地降低声呐的检测能力，影响水声通信的应用频段和降低水声设备的性能。考虑未来的海战极可能是在恶劣天气（往往伴随疾风暴雨）下进行，充分掌握降雨噪声的特性，不仅在军事上有利于检测海洋环境噪声背景中的干扰源，提升水声设备的作战效能，而且在民用上可拓展应用声学方法监测海上降雨的技术。近几十年来，美国等发达国家为了解释降雨噪声的产生机制，对自然界的降雨噪声开展了大量观测。前期的研究成果表明，降雨噪声的功率谱分布与空中降雨强度大小息息相关。但是，由于受限于降雨噪声的观测和数据获取的诸多困难与不确定性，现有的工作仍以揭示降雨噪声...When precipitation falls on the water surface, an acoustic signal with broadband frequency and strong intensity will be radiated in oscillogram pattern. It is now known as rain noise. As one of loudest sources, the intermittent rain noise can decrease the detection ability of sonar, affect the application frequency bands of underwater acoustic communication and reduce using performance of part of ...学位：理学博士院系专业：海洋与环境学院海洋学系_海洋物理学号：2242008015012

Underwater sound effects generated by tunnel-explosion near the coastal harbor

以福建省罗源县正在建设的龟屿隧道爆破工程为例,分析了隧道爆破地震波的传播规律和对毗邻大黄鱼育苗池的水中声场环境的影响。研究结果表明:(1)爆破作业将显著地增加毗邻大黄鱼育苗池的水中声强(比未爆破前的水中声强高约60~80db),强度的增加与爆破药量成正比,与爆点的距离成反比,且距离的影响远大于爆破药量的影响;(2)在海水高潮和低潮的2个时段,由于爆破地震波传播途径的不同,毗邻大黄鱼育苗池的水中声场环境在强度和频率能量分布上均存在差异:育苗池中低潮时段的水中声强小于高潮时段的水中声强;低潮时段声波能量主要分布在小于400Hz的较低频带上,而高潮时段的声波能量主要分布在200~1 000Hz的较高频带上。因此,为减小隧道爆破对育苗池中大黄鱼的伤害,结合分析大黄鱼对水中声波的敏感频率(500~800Hz)及敏感强度,需降低育苗池的水中声强并使声波能量分布向低频带转移,选择在低潮时段、采用低药量进行隧道作业。Underwater sound effects generated by tunnel-explosion were studied and an observation was performed to monitor the underwater sound pressure in Pseudosciaena crocea's breeding pond when Guiyu tunnel blast engineering occurred thither coastal harbor in Luoyuan County,Fujian Province.Based on acoustic theory of transmission and reflection on solid-fluid interface,the results show that blasting seismic wave makes impact on underwater environment through two kinds of sound transmitted paths.The underwater sound intensity increases sharply(up to 150 dB) in breeding pond when Guiyu tunnel blast engineering occurs,and the increment of sound intensity is directly proportional to the mass of explosives as well as which is inversely proportional to the distance from blasting point.However,the effect of distance is greater than that of mass.Additionally,at different time of low tide and high tide,the sound intensity generated by blasting seismic wave in pond has a significant difference due to the two paths of sound propagation in different transmitted media.With the increment of distance,sound intensity at low tide time declines more quickly than that at high tide time.Similarly,the sound energy distribution in frequency band has different shape.Sound at high tide time is dominant in frequency band of 200～1 000 Hz.On the other hand,the frequency of sound in pond at low tide time is mainly less than 400 Hz.The greater of the water depth above seabed is,the lower of the cut-off low frequency is for underwater acoustic waveguide effect.Consequently,the low tide time for Guiyu tunnel blasting should be chosen so that it can decrease the harm of high intensity in Pseudosciaena crocea's breeding pond,avoiding to do harm to pseudosciaena crocea's body in the sound resonant frequency of 500～800 Hz.教育部博士点基金项目(20090121110001);福建省科技计划重点项目(2009N0050

Behavioral responses of captive bottlenose dolphins(Tursiops truncatus) to a continuous 20 kHz pure tone

将20 kHz连续声信号作为刺激信号,测试了厦门某海湾圈养的两只瓶鼻海豚对该信号的行为变化。通过对比信号发射期与间歇期海豚相对声源的水面距离、露出水面的次数以及水下发出的ClICk定位声信号的数目等变化,判断发射信号对海豚行为的影响。给出了瓶鼻海豚对测试信号产生躲避行为的声压级门限(154±2 db rE 1μPA,rMS),并与鼠海豚的躲避声压门限级进行了对比。结果表明:信号发射期,瓶鼻海豚移离了声源位置,增加了露出水面的次数,水下发出ClICk声信号的次数明显减少。因此,瓶鼻海豚对20kHz连续信号产生了行为改变。Two captive bottlenose dolphins housed in a float cage in a Bay were subjected to a continuous 20 kHz tonal signal.The behavioral responses of dolphins were judged by comparing the surface distances relative to the sound source,number of surfacings,and number of the echolocation clicks production of the dolphins,during test periods and baseline periods.The avoidance threshold sound pressure level(SPL)for a continuous 20 kHz tonal signal for the bottlenose dolphins was estimated to be 154±2 dB(re 1μPa,rms).In addation,the comparison between the avoidance threshold SPL for harbor porpoises to a 50 kHz continuous signal and bottlenose dolphins to a 20 kHz continuous signal was also studied.The results showed that the dolphins moved away from the sound source and came to the surface more frequently during the test periods than the baseline periods,but they produced clicks significantly fewer.Therefore,a continuous 20 kHz tonal signal seems to deter bottlenose dolphins from an area.国家海洋局青年科学基金(2010422);海洋公益性行业科研专项(201105011-3)项目;国家海洋局第三海洋研究所基本科研业务专项(海三科2009010)资

Study on the Characteristics of Echolocation Clicks from Indo-Pacific Humpback Dolphins(Sousa chinensis) in Xiamen

对厦门海域中华白海豚的发声及信号特性进行研究,采用高频宽带数据记录系统获取了大量中华白海豚ClICk信号,并利用MATlAb软件和EXCEl 2007对这些信号进行时域和频域分析.结果表明:ClICk信号通常以不同长度的序列形式出现,单个ClICk信号长度分布在(33±4)μS;频谱能量分布广,低频至10kHz,高频达200kHz以上,具有单峰和双峰2种频谱结构,峰值频率、3db带宽和10db带宽分别为(113.3±16.3)、(48.3±14.2)和(113.3±16.4)kHz.中华白海豚ClICk信号双峰的频率分布,为其在海底混响严重的浅海环境准确识别目标提供了保障.The vocalizations and signal characteristics of humpback dolphins(Sousa chinensis) in Xiamen were studied in this paper.A large number of original click signals were obtained by a broad frequency-band recording system.These signals were analysed as waveforms and spectrograms using Matlab tool and Excel 2007.Results of this study indicate that clicks of humpback dolphins occur as trains.The duration of each click trains vary wildly,ranging from a few seconds to tens of seconds,but single click have a short duration around(33±4) μs.The echolocation clicks have a wide range of frequency distribution between 10 kHz and 200 kHz.Click signals have two types of spectrum structure and have an averaged peak frequency of(113.3±16.3) kHz with 3 dB bandwidth of(48.3±14.2) kHz.The 10 dB bandwidth of(113.3±16.4) kHz is also given in the results.Most of the echolocation clicks have a bimodal frequency distribution,which provides a good range resolution capability that should enable dolphins to be able to perform fine target discrimination in a shallow water environment where bottom reverberation can be troublesome.海洋公益性行业科研专项(201105011-3);中国博士后科学基金项目(2011M501082

A Method of Acoustic Transmission Loss Calculated with Background Noise Removal-energy Summation

利用常规声传播损失方法计算实测水声场信号时,发现在低信噪比下计算得到的声传播损失存在较大误差.因此,利用能量谱去噪声原理,改进了常规声传播损失的计算方法,并比较分析了2种方法的结果.研究结果表明:当海洋环境条件较复杂、不易区分干扰源时,或者在低信噪比下的远程水声传播中,采用改进的声传播损失计算方法能够较好地抑制噪声、有效地提取信号能量和提高信噪比.A method of background noise removal-energy summation was introduced in the paper to improve the estimable precision of acoustic transmission loss of measured signals.By using an old general FFT energy summation method to calculate the acoustic transmission,a lower detectable precision was found in measured long-range sound propagation signals.In order to improve the estimable precision,the paper come up with a modified method named background noise removal-energy summation to calculate acoustic signals based on the general FFT energy summation.Then,the result showed that the experimental transmission losses with the new method were agreed well with the model-simulated data.Therefore,the using of background noise removal-energy summation method in signal processing is more effective to extract the real signal energy and has the capacity of improving signal to noise ratio.福建省科技重点项目(2006N0042)资

Simulation study on the time-varying multipath model for underwater acoustic channel

本文针对浅海水声信道的时变特性,基于射线理论引入海洋参数———强度起伏参数Φ、不均匀度参数Λ,建立有效的时变多径信道模型,并采用MATlAb工具进行仿真.仿真结果表明,该模型相比于确定性模型更容易理解、更真实.文中给出的模型和结论能够为实际通信系统中发射接收机深度等的选择和设计提供一定的参考和依据,有助于对水声信道的了解.According to time-varying characters of underwater acoustic(UWA) channel,an effective model of time-varying multipath channel based on ray theory is developed.In the model,two important ocean parameters,the strength parameter Φ and the size parameter Λ,are introduced.Through computer simulation,the model provides more intelligible and realistic results than the deterministic model.The simulation results offer a certain reference and basis for analysis and design of the receiver depth,which is helpful for understanding the character of the UWA channel.国家海洋局第三海洋研究所基本科研业务费专项基金资助项目(2009049

Study on behavior of sound stimulation for large yellow croaker (Pseudosciaena crocea)

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10 PA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800 Hz和600 Hz,直接致死的声压阈值约为40 PA和4 kPA.13个月大鱼的声波敏感频率也在600 Hz,但当声压达到4 kPA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48 H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.An experiment of hearing sensitive test for 3 different ages of large yellow croaker( Pseudosciaenacrocea) was carried out for behavioral observation to understand the impact of injury levels by underwater strong noise.The results showed that all 3 age fish generated condition response when the underwater sound pressure reached approximately 10 Pa.However,their hearing threshold and acoustic sensitive frequency were significantly different.The hearing thresholds of direct mortality for 1-month seedling and 8-month fish were 40 Pa and 4 kPa respectively.Similarly,the acoustic sensitive frequencies were 800 Hz and 600 Hz.For 13-month fish,despite its acoustic sensitive frequency at 600 Hz,no direct mortalities but significantly frightened were found when the sound pressure climbed to 4 kPa.Additionally,the fishes exposed by strong sound pulses in the experiment tend to die-offs in 48 hours.The analysis show that the fishes exposure long to underwater sound pulses may have cause cumulative effects of behavior pattern change and indirect chronic hazards when noise persisted.国家海洋局第三海洋研究所基本科研业务费专项资助项目(海三科2012022); 国家海洋公益性行业科研专项资助项目(201105011-3

Mercury concentration and biological quality index of major fish species from Dongzhaigang mangrove forest area of Hainan

汞可以通过鱼类富集,危害人类健康。为了解东寨港红树林区鱼类的汞含量及其生物质量,本研究对林区内14种主要鱼类和不同环境介质的汞含量进行了分析。研究发现,鱼肉汞平均含量为67.7 ng.g-1,变化范围为34.9--154.9 ng.g-1。海水、红树植物叶片、沉积物中汞含量分别为0.4μg.l-1、153.9 ng.g-1、314.1 ng.g-1。相对于海水,鱼对环境中的汞具有明显的生物富集作用,鱼体汞含量与其食物来源和生活习性有关,杂食性鱼类汞含量高于植食性鱼类和肉食性鱼类汞含量。所有鱼类体内的生物质量指数均<1,可安全食用。Mercury can threat human health through fish enrichment.In order to understand the mercury concentration and biological quality of major fish species in Dongzhaigang mangrove forest area of Hainan,this paper analyzed the mercury concentrations of 14 main fish species and different environmental media in this forest area.It was detected that the mercury concentration in fish muscle was 34.9-154.9 ng·g-1,with an average of 67.7 ng·g-1,and that in sea water,mangrove leaves,and sediments was 0.4 μg·L-1,153.9 ng·g-1,and 314.1 ng·g-1,respectively.Relative to sea water,the fishes enriched more mercury from the environment.The mercury concentration in the fishes was related to their food sources and living habits.Omnivorous fish had higher mercury concentration than herbivorous fish and carnivorous fish.All the fishes had the biological quality index lower than 1,being safe as foods.国家自然科学基金项目(40676064和40876046)资

Mixed-program of Visual Basic 6.0 and Matlab for ocean chemistry data processing

主要阐述了应用Visual Basic 6.0中的ActiveX技术把Visual Basic的可视化设计同Matlab处理数据的优越性结合起来处理海水水质测量实验数据,从而大大简化实验数据处理的繁琐,提高了工作效率。Combining the advantages of Matlab data-processing capability with Object Oriented design of VB 6.0 by AcitiveX, a mixed program is established to process measured data from sea-water quality experiments, which can save time and simplify data processing.福建省青年科技人才创新基金(2003J045

中国珍稀濒危冷杉的发现、现状及未来

百山祖冷杉、梵净山冷杉、元宝山冷杉和资源冷杉是中国特有的珍稀濒危植物,均被列为国家Ⅰ级重点保护植物。目前,这4种濒危冷杉在我国东南部亚热带山地呈空中岛屿状间断分布,且均分布在近山顶地区。面对全球气温的不断上升,它们缺乏足够的高海拔低温生境可供迁移,取而代之的将是生境的进一步压缩和破碎化。而横断山地区由于复杂的地形和多样化的生境而成为最合适冷杉生存的栖息地,可作为这几种冷杉的迁地保护中心