“老师”住在海里 ——海洋动物仿生学

海蜇,早在5亿多年前就漂浮在海洋里,是一种极古老的腔肠动物,还是预报风暴最早、最准确的“顺风耳”。因为它的“耳朵” (细柄上的小球)中有小小的听石,风暴产生时发出的次声波(由空气和波浪摩擦而产生,频率为8赫兹～13赫兹,传播比风暴、波浪的速度快)冲击小小听石“球”壁的神经感受器,于是海蜇就隐约听到了即将来临的风暴的隆隆声,便警惕地离岸游向大海避灾。     

《海岸工程》第26卷(2007年)总目次

第1期辽东湾绥中海岸侵蚀研究……………………………………………王玉广,张宪文,贾凯,王权明(1)计算分析潮流对海缆路由稳定性的影响……………………张效龙,徐家声,王慧艳,刘敦武,迟万青(6)海洋路由勘测对海底光缆工程的影响分析……………………………………………董秀春,董向华(11)基于MapX和GPS的油田作业平台就位服务系统研究……………………雷宁,周兴华,王振宇(15)激光扫描测量技术在海洋测量领域中的应用及技术发展趋势………………………………………………………………………………丁继胜,刘建立,范学炜(21)次声波在海啸灾害预…     

交通地理网络分析模型的实现

首先介绍了网络分析的概念,接着介绍了交通网络的基本要素,然后建立了交通网络的模型,通过确定影响交通体系中网络流的因素,实现了最优路径的选择,最后用具体的数据验证了模型的合理性。     

中国海监开展巡护执法全力保障大运 中国海监广东省总队

为确保大运会期间相关安保工作的顺利进行,中国海监广东省总队根据上级部署成立了领导机构,制定了方案,明确了五项重点任务:一是确保渔区、渔港、渔船、渔民稳定,二是确保海底国际光缆安全,三是确保大运会水产品有效供给,四是做好野生动物保护工作,五是做好海上安保工作。同时组织召开了关于大运安保的专门执法会议,细分任务、积极备战,并启动了24小时值班制度,开展了一系列的执法行动,取得了较好的效果,为大运会海上安保工作打下了坚实的基础。     

渤海油田电潜泵从采购模式到租赁模式实践

电潜泵是海上平台重要的采油设备,它的供货周期和生产时效关系到整个油田的产量和成本。以渤海油田为例,介绍了电潜泵从采购到租赁模式的转换,简化了电潜泵的采办程序,缩短了供货周期,提高了作业时效,延长了电潜泵的检泵周期。租赁模式的推广应用,取得了明显的效果。     

陆源污染物对连云港海域环境影响研究

应用沿深平均二维模型模拟了连云港海域的潮流场,分析了该海域的潮波特性,在此基础上,应用扩散方程对连云港海域的水污染扩散进行了数值模拟,得到了港域水体的半交换期;比较分析了西大堤对该水域水交换的影响;计算了港域水体的Lagrange余流场,并分析了其对污染物运移的影响,得到了港域几个典型位置的Lagrange轨迹;计算了港域的纳潮量,综合分析了港域水体的物理自净能力。     

辽宁省海洋渔业综合管理数据服务平台建设概述

本文介绍了辽宁省海洋与渔业信息化现状,分析了现有系统存在的不足,并在此基础上建设了辽宁省海洋渔业综合管理数据服务平台,对现有信息化系统进行了梳理,实现了全省教据资源的统一管理与共享;开发了若干面向业务应用的子系统,实现了对海洋渔业管理的全方位支持;建设了数据交换共享标准与服务接口,为日后的信息化建设提供了有力的技术支撑手段。     

海塘滩涂管理信息分类编码与图式标准研究

归纳整理了涉及海塘滩涂管理的信息数据,界定了海塘滩涂管理信息的各种术语,规定了海塘滩涂管理信息的分类体系和编码,确定了海塘滩涂管理信息的GIS图式符号标准,制定了海塘滩涂管理信息的属性表,为海塘滩涂管理信息的采集、存储、共享和交换奠定了基础。     

深海微生物培养模拟平台温度控制技术研究

针对深海微生物培养系统对温度条件的苛刻要求,在分析系统构成及建模的基础上,介绍了一种对系统的两级滞后环节采用了PI控制和双Smith预估反馈的方法,通过内环和外环Smith预估控制,精确的消除了温度控制系统中滞后延迟环节的影响,提高了PI控制强度,减少了超调,提高了系统动态响应和稳态精度。在系统Matlab仿真和实际实验中得到了良好的效果,满足系统的精度要求。     

罗兰C和北斗组合导航系统定位精度研究

以双曲线定位原理实现了罗兰C／北斗组合导航,提出了HDOP的定义,以此分析了两系统组合前后的定位精度,并给出了定位精度的仿真。结果表明,组合后大大改善了罗兰C定位精度和定位可用范围,并弥补了北斗定位系统有源定位的不足。     

Absorption of infrasonic waves in a cloudy medium

We study the absorption of infrasonic waves when they are propagating in cloud media. In this case, the main mechanism of absorption is the relaxation processes associated with vapor-drop phase transitions caused by infrasonic waves. For frequencies comparable to the inverse relaxation time, the acoustic waves in a cloud medium were shown to have a noticeable dispersion. We derive an expression for the frequency-dependent effective adiabatic index linking the oscillations of pressure and density in the wave, the dispersion equation, and the expression for the absorption coefficient. For typical values of cloud parameters, the absorption coefficient was estimated to be around 0.1 km^?1. We discuss observation data which indirectly confirm that clouds can considerably absorb infrasonic waves.     

Using the acoustic-pulse conservation law in estimating the energy of surface acoustic sources by remote sounding

The atmospheric effect on the characteristics of infrasonic signals from explosions has been studied. New methods have been proposed to remotely estimate the energy of explosions using the data of infrasonic wave registration. One method is based on the law of conservation of acoustic pulse I, which is equal to the product of the wave profile area S/2 of the studied infrasonic signal and the distance to the source E_I [kt] = 1.38 × 10^–10 (I [kg/s])^1.482. The second method is based on the relationship between the explosion energy and the dominant period T of the recorded signal, EТ [kt] =1.02 × (Т [s]²/σ)^3/2, where σ is a dimensionless distance used for determining the degree of manifestation of nonlinear effects in the propagation of sound along ray trajectories. When compared to the conventional E_W (Whitaker’s) relation, the advantage of the EI relation is that it can be used for pulsed sources located at an arbitrary height over the land surface and having an arbitrary form of the initial-pulse profile and for any type of infrasonic arrivals. A distinctive feature of the expression for E_Т is that the atmospheric effect on the characteristics of recorded infrasonic signals is explicitly taken into account. These methods have been tested using infrasonic data recorded at a distance of 322 km from the sources (30 explosions caused by a fire that occurred at the Pugachevo armory in Udmurtia on June 2, 2011). For the same explosion, empirical relations have been found between energy values obtained by different methods: E_I = 1.107 × E _W , E _Т = 2.201 × E _I .     

On experience in using the method of morphological data analysis in atmospheric acoustics

A methodical system has been developed to solve the problem of isolating informative signals against the background of noise which is based on a morphological analysis. It is shown that the morphological method of analyzing infrasonic signals is an effective instrument to isolate infrasonic signals, to analyze the features of their forms, and to estimate their relative delays. The advantage that the morphological method has over the correlation method in analyzing short signal fragments recorded by infrasonic microphones spaced at distances that significantly exceed the signal wavelengths is shown.     

Studying possibilities for the classification of infrasonic signals from different sources

Atmospheric infrasonic signals were classified on the basis of data obtained in the United States (University of Alaska, Fairbanks) and in the Antarctic region (Windless Bight) from 1980 to 1983. The data archive included five classes of signals from different sources: explosions, mountain associated waves, microbaroms, volcanic infrasound, and auroral infrasonic waves. This classification was based on the theory of testing statistical hypotheses. The possibilities of separating these classes were studied. It was shown that the signals (from the archive used) that are characteristic of explosions and volcanic activity can be rather easily separated from those characteristic of mountain associated waves, microbaroms, and auroral infrasonic waves.     

Acoustic positioning for an array of freely drifting infrasonic sensors

Initial testing of the prototype element of a freely drifting infrasonic sensor array is described. The intent of this measurement system is to gather wide aperture data sets which will be used both to characterize ambient noise in the region 1-10 Hz and to assess the gains possible from beam forming utilizing a collection of very low frequency (VLF) sensors. Coherent processing (beam forming) of the infrasonic sensor data is made possible by relative position measurements derived from mutual acoustic interrogation of the elements at a higher frequency. Surface echo data from a recent sea test of the prototype buoy are used to illustrate the type of pulse processing which will be implemented as a first step in the localization procedure.     

Analyzing Conditions for the Occurrence of the Voice of the Sea on the Basis of Infrasound Measurements

Izvestiya, Atmospheric and Oceanic Physics - Conditions for the occurrence of the “voice of the sea” within the infrasonic range are studied and its parameters are determined from...     

Infrasound scattering from atmospheric anisotropic inhomogeneities

A model of anisotropic fluctuations forming in wind velocity and air temperature in a stably stratified atmosphere is described. The formation mechanism of these fluctuations is associated with the cascade transport of energy from sources of atmospheric gravity waves to wave disturbances with shorter vertical scales (than the scales of the initial disturbances generated by the sources) and, at the same time, with longer horizontal scales. This model is used to take into account the effects of infrasonic-wave scattering from anisotropic inhomogeneities of the effective sound speed in the atmosphere. Experimental data on the stratospheric, mesospheric, and thermospheric arrivals of signals (generated by explosion sources such as surface explosions and volcanoes) in the zones of acoustic shadow are interpreted on the basis of the results of calculations of the scattered infrasonic field in the context of the parabolic equation. The signals calculated with consideration for the fine structure of wind velocity and air temperature are compared with the signals observed in a shadow zone. The possibility to acoustically sound this structure at heights of both the middle and upper atmospheres is discussed.     

Nonlinear effects manifested in infrasonic signals in the region of a geometric shadow

Nonlinear effects manifested in infrasonic signals passing through different atmospheric heights and recorded in the region of a geometric shadow have been studied. The source of infrasound was a surface explosion equivalent to 20–70 t of TNT. The frequencies of the spectral maxima of infrasonic signals, which correspond to the reflections of acoustic pulses from atmospheric inhomogeneities at different heights within the stratosphere-mesosphere-lower thermosphere layer, were calculated using the nonlinear-theory method. A satisfactory agreement between experimental and calculated data was obtained.     

Simulating the Propagation of Infrasonic Waves and Estimating the Energy of the Chelyabinsk Meteoroid Explosion Observed on February 15, 2013

Results obtained from simulating the propagation of infrasonic waves from the Chelyabinsk meteoroid explosion observed on February 15, 2013, are given. The pseudodifferential parabolic equation (PDPE) method has been used for calculations. Data on infrasonic waves recorded at the IS31 station (Aktyubinsk, Kazakhstan), located 542.7 km from the likely location of the explosion, have been analyzed. Six infrasonic arrivals (isolated clearly defined pulse signals) were recorded. It is shown that the first “fast” arrival (F) corresponds to the propagation of infrasound in a surface acoustic waveguide. The rest of the arrivals (T1–T5) are thermospheric. The agreement between the results of calculations based on the PDPE method and experimental data is satisfactory. The energy E of the explosion has been estimated using two methods. One of these methods is based on the law of conservation of the acoustic pulse I, which is a product of the wave profile area S/2 of the signal under analysis and the distance to its source E _I [kt] = 1.38 × 10^–10 (I [kg/s])^1.482. The other method is based on the relation between the energy of explosion and the dominant period T of recorded signal E _T [kt] = 1.02 × (T [s]²/σ)^3/2, where σ is the dimensionless distance determining the degree of nonlinear effects during the propagation of sound along ray trajectories. According to the data, the explosion energy E _I,T ranges from 1.87 to 32 kt TNT.     

Determining places of falling of launch vehicle fragments using infrasonic observations

A procedure for locating the places of falling of fragments of a launch vehicle (LV) by recording the infrasonic signals is presented. The algorithms for generating pipes of real trajectories of falling fragments, for calculating signal parameters (sound propagation in the atmosphere), and for comparing the theoretical and experimental parameters are examined. The ways atmospheric parameters influence calculation accuracy is estimated.