An overview of statistical methods applied to CPR data

Since the beginning of the Continuous Plankton Recorder (CPR) survey in 1931, information on the abundance of a large number of plankton species or taxa has been obtained on a monthly basis in the northern North Atlantic. The many different ecological issues in which the survey has been involved have led to the application of a range of statistical methods. In this paper, we review some of the methods applied to the CPR data by presenting new and up-to-date analyses. Special attention is devoted to multivariate analysis, which has been used extensively to extract information from the CPR database. Results obtained from recently applied geostatistical methods on CPR data are then considered. An example of a time series decomposition by the use of Eigenvector filtering is presented to illustrate time-series analysis.     

海洋平台结构损伤识别与定位新方法及试验验证

基于小波变换的时频局域化特性和BP神经网络的非线性映射特性,结合两者优点提出了基于小波包分析和神经网络方法的海洋平台三步法损伤定位方法。对海洋平台结构加速度响应信号进行小波包分析,提取小波包特征向量,将小波包结点能量变化量指标作为BP网络的输入向量,逐步确定损伤位置。设计一典型导管架式海洋平台试验模型,分别进行岸上脉冲激励及水池中波浪激励下平台结构损伤识别与定位模型试验,对该方法的可行性和适用性进行了验证。     

海洋放线菌不同分离方法的比较研究

采用平板涂布法,以青岛海区潮间带沉积物为对象进行海洋放线菌的分离方法研究.具体分析了不同样品预处理方式、稀释液、海水浓度和培养基种类等对分离效果的影响.结果表明,55℃预处理样品6 min能有效减少细菌数量,利于潮间带沉积物中放线菌的分离;以1/4林格氏溶液稀释样品、纯海水配置培养基,可以分离得到较多的放线菌;不同培养基对沉积物中放线菌的分离效果差别很大,本实验设置的M1 ～ M9培养基中,M1、M6、M7和M8培养基的分离效果优于其他5种.     

Simulations of an adaptive equalizer applied to high-speed oceanacoustic data transmission'

Computer simulations are carried out to study the feasibility of an adaptive equalizer applied to an hydroacoustic data-transmission channel. The channel is examined with a comprehensive acoustical model to acquire worst-case examples of the ocean acoustic transmission channel. The equalizer performance is investigated by simulations with a computer-generated channel response. Equalizer behavior in a mobile time-variant environment is also studied by use of a simplified, time-discrete multipath channel model. A stochastic gradient lattice equalizer is simulated for a channel which varies due to movement of the transmitter platform. The equalizer was able to track a velocity of up to 0.4 m/s for a favorable transmission geometry, using a transmitter beamwidth of 10°. The results demonstrate the feasibility of coherent modulation schemes for medium-distance ocean acoustic telemetry. It was found that small beamwidths are imperative in maintaining signal coherence and in facilitating adaptive equalization. In particular, narrow-beam transducers will reduce equalizer complexity as well as the frequency spread     

基于 MODWT航行数据滤波方法变换的海洋重力观测

厄特弗斯效应是动态海洋重力测量的主要误差来源,厄特弗斯改正精度与航速和航向角精度密切相关。本文从最大重叠离散小波变换系数的分布特性入手,利用改进的定量化 Lipschitz 条件来确定观测曲线的正则性,提出了一种海洋重力观测中含噪航行数据的滤波方法,该方法在抑制噪声干扰的同时能够很好地保留测量信号的局部特征。本文提供了两组海洋重力测量中航速和航向角数据的处理结果,充分验证了本文方法的可靠性与有效性。     

海洋沉积物黏土矿物相对含量不同计算方法对比研究

海洋沉积物黏土矿物相对含量计算存在多种计算方法,并不统一,限制了异源黏土矿物的整合和使用。文章选取了两种较为常见的计算方法,即Biscaye和国标中规定的计算方法,分别对东印度洋109个表层样品黏土矿物的相对百分含量进行计算,分析对比了两种方法计算结果之间的差异。结果显示,两种计算方法结果存在显著正相关,都能显示黏土矿物分布的变化趋势,4种黏土矿物相关系数由高到底分别为:蒙皂石0.986、伊利石0.974、绿泥石0.924、高岭石0.923。相对于Biscaye计算方法,国标计算方法会增加伊利石和高岭石的相对百分含量而降低蒙皂石和绿泥石的相对百分含量。两种计算方法黏土矿物的含量相关性较好,可以建立起相互数学转换关系式。但在不同的海区,由于矿物成因、结晶程度以及混层矿物的出现可能会使衍射峰形态发生改变,从而相关性系数和转换关系也会相应发生改变。     

HY-1 CCD宽波段水色要素反演算法

利用2003年春季黄海、东海区现场实测数据,建立了HY1卫星4波段CCD成像仪水色要素反演算法.由于HY1CCD的宽波段特性阻碍了黄色物质的反演,因此反演的水色要素仅包括水体表层的总悬浮物、悬浮泥沙(SS)以及叶绿素a的浓度.现场遥感反射率光谱由ASD地物波谱仪测量,对于叶绿素a的浓度利用现场萃取荧光法测量,总悬浮物、悬浮泥沙由实验室滤膜称重法获得.反演算法的拟合相关系数均大于0.88,平均相对误差在40%以下.对反演算法进行了误差灵敏度分析,结果表明对于总悬浮物、悬浮泥沙和低浊度水体中的叶绿素a的浓度反演算法能够满足日常的业务运行要求,但是对于高浊度水体中叶绿素a的浓度反演算法对某个波段组合比较敏感,仍需要进一步探讨.     

两种基于贝叶斯点估计理论的多声源定位方法研究

海洋环境参数失配是制约匹配场定位性能的主要因素之一。为了克服环境失配,本文基于贝叶斯理论,将环境参数与声源的距离和深度一起作为未知量进行反演。然而在进行多声源定位时,反演参数的维数几何增长,极大地增加了反演问题的复杂性和计算量。为此本文将声源强度和噪声方差表示成其极大似然估计值,从而将这些参数进行隐式采样,大大降低了反演的维数和难度。文章比较了两种贝叶斯点估计方法,最大后验概率密度方法和最大边缘后验概率密度方法。最大后验概率密度方法的解是令后验概率密度取得最大值的参数组合,可以利用优化算法快速获得。最大边缘后验概率密度法将其他参数积分,得到目标参数的一维边缘概率分布,分布的最大值为反演结果。该方法得到最优估计值的同时可以获取参数估计的不确定信息。在环境参数和声源参数都未知的情况下,利用蒙特卡洛法在不同信噪比情况下对两种声源定位方法进行分析,实验结果表明：(1)对于敏感参数,如声源距离、水深和海水声速,最大边缘后验概率密度法比最大边缘后验概率密度方法的性能好。(2)对于较不敏感的参数,如海底声速、海底密度和海底声衰减,当信噪比较低时,最大边缘后验概率密度方法能较好地平滑噪声,从而比最大边缘后验概率密度法具有更好的性能。由于声源距离和深度是敏感参数,研究表明最大边缘后验概率密度法提供了一种在不确知环境下更可靠的多声源定位方法。     

NOS study of applied photobathymetry

Classical hydrographic mapping in shallow waters with surface craft is slow, hazardous, and expensive. The remarkable water penetration capability of several currently used film emulsions and their dramatic presentation of submerged detail provides an alternative tool and supplement for mapping the seabed in shoals and waters of moderate depth. Photogrammetric bathymetric surveys preceding hydrography can show many of the rocks, reefs, shallow areas, photogrammetrically observed depth measurements and depth curves, and other features and thereby assist the hydrographers whose work is more difficult because they do not have the overall view of the bottom to guide their operations in developing important details. The objective of this paper is to advance the comprehension of the potential of photogrammetric bathymetry to provide the following benefits: (1) improve the accuracy and completeness of the hydrographie survey; (2) reduce the cost and time of the field hydrographie survey; and, (3) reduce ship requirements for a particular hydrographic survey, thereby releasing some of the craft for other assignments and/or enlarging the size of the coastal water areas that can be surveyed within a given time frame. The investigation of the potential for accomplishing photogrammetric bathymetry was restricted to ten regions of high priority along the East Coast and the Gulf of Mexico. A five‐year photobathymetry program is envisaged that will require a maximum of 10,765 man‐days of work and cost $1,154,750. These figures can be substantially reduced by employing digitized stereoscopic plotting instruments and developing advanced, sophisticated photogrammetric analytic aerotriangulation procedures.     

Micromechanical damage modeling and simulation of punch test

In order to verify the validity and applicability of the porous plasticity model for the simulation of non-local plastic fractures, punch tests are carried out for round steel plates of JIS G3131 SPHC. Incremental tensile coupon tests for the material are also conducted to obtain the plastic mechanical properties. Material parameters required for the porous plasticity model are identified through parametric numerical simulations of the coupon tests. It is proved that that force vs. indentation curves from punch test simulations using the porous plasticity model with the identified material parameters show good agreement with punch test results. It is also verified that simulated fracture shapes in the punch specimens are almost similar to the experimental ones in which fracture occurs along the circumferential edge of indenter where the hydrostatic stress develops highly.     

超短基线定位原理及校正方法研究

通过探讨超短基线和GPS技术相结合的三维立体定位原理,分析超短基线定位误差来源,如安装偏差、声速误差、船姿态变化引起的偏差等,利用以最小二乘法为理论基础的动态校正法对超短基线定位误差进行了修正,将校正前后的定位数据标准偏差和剩余偏差处理后对比发现,这种方法可以极大地提高水下目标定位的精度,减少定位的误差,这也在实际应用...     

Development of means and methods of drifter technology applied to the problem of the Black Sea research

During the last ten years, autonomous drifting platforms for data collection (drifters) equipped with Argos satellite communication devices have become one of the main components for the observation system in the upper layer of the ocean and surface atmosphere. This article presents the results of the Black Sea drifter monitoring in 2002–2006 within a number of international programs and projects. During this period, about 70 drifters manufactured by NPF Marlin-Yug Ltd. (Sevastopol, Ukraine) were deployed in the western part of the Black Sea. The drifters were mainly standard barometric Lagrangian tracers and a part of them were principally new temperature profiling buoys. Unique long-term data were obtained about the circulation of the surface currents and the dynamics of the temperature stratification within the seasonal thermocline and the cold intermediate layer.     

Comparative analysis of the methods used for the determination of the optical parameters of waters in the black sea according to the data of satellite measurements

We demonstrate the possibility of determination of the spectral characteristics of absorption and backward scattering of light in the Black Sea according to the data of a SeaWiFS satellite device. We use specially selected data of observations obtained under favorable atmospheric conditions. It is shown that the results of calculations performed by using different methods are almost identical and weakly depend on the model parameters of the spectral course of the coefficients of absorption of light by yellow substance and its scattering by suspended particles.     

涡激振动实验中的流速增大装置研发与性能研究

拖曳水池中进行立管涡激振动实验时,为了保证采样时间长度,难以达到较高的Re数。流速增大装置可以在不提高拖车车速的情况下增大立管外的流速。利用这种流速增大装置还可实现流速分层流场中细长柔性立管涡激振动实验。经过对流速增大装置中的进流段曲线进行优选,发现Witozinsky曲线的总体性能最好。在对流速增大装置进行水池实验和数值模拟后,发现流速增大区域的流速增大倍数接近进流段收缩比,流速增大区域流场比较稳定、均匀,流速增大装置对其外的流场影响很小。此流速增大装置不但可应用于拖曳水池中的立管涡激振动实验,还可以应用于对流速要求较高的水下航行体的水池试验,如鱼雷、水下机器人等。     

海水养殖池塘赤潮危害的应急治理措施

由于近海水域生态环境因素的变化 ,赤潮生物常常侵袭到海水养殖池塘中 ,给养殖业造成严重威胁。根据多次处理海水养殖池塘受赤潮生物危害的经验 ,对赤潮的认识、常用赤潮治理药物的使用、赤潮生物大量形成后的处理方法作一些简要介绍。     

三种典型POPs对紫贻贝不同组织DNA损伤的比较研究

采用彗星电泳技术,比较研究了Aroclor 1254、BaP、DDT三种典型POPs对紫贻贝(Mytilus edulis)鳃、性腺、消化腺细胞的DNA损伤效应的差异,以期为进一步评价这三种典型POPs遗传毒理机制及其预警监测提供科学依据.结果表明,Tail DNA%是评价DNA损伤的理想指标,另外,在急性毒性试验中,...     

局部多项式插值方法在多源海底沉积厚度数据融合中的应用

提出了在多源空间数据融合过程中出现不一致的问题;介绍了局部多项式插值方法的基本原理;通过该方法在海底沉积厚度模型构建中的成功应用,为基础数据的搜集和融合提供了新的思路.     

SNMP与NetStream流量监控方法的对比分析

随着海洋信息通信网业务需求量的日益增加,以及用户对网络性能要求的提高,网络管理必不可少,而流量监控和统计分析是网络管理的基础.本文主要对海洋信息通信网中不同的流量监控技术进行研究,通过分析海洋信息通信网网络监控现状、SNMP流量监控技术、NetStream流量监控技术以及通过对比对两种监控手段在海洋信息通信网中的差异,...