基于GIS水团分析集成系统的开发及其应用

水团的识别与划分一直是物理海洋学的重要研究内容。本研究采用模糊密度聚类方法划分水团，并利用Fortran语言编制了该模型：同时，在Visual Basic 6．0环境下，利用MapX控件进行了GIS平台开发；并将两者紧密集成，使得水团分析的所有阶段，包括计算网格的获取、温盐场数据的提取和插值、模型的参数选择和设置、模型的计算以及最终结果的可视化等都在同一环境下完成，大大提高模型应用的数据分析和决策的效率。将该系统应用于舟山渔场及其邻近海域，所得结果比较理想。     

变性水团软划分的一种FUZZY模式

在已知研究海区水团核心的前提下,考虑到各种指标对标识水团的不同贡献,提出了一种水团软划分的FUZZY模式。利用1987年5—6月黄东海的温、盐和溶解氧实测资料进行计算,与已有成果作了对比,结果令人满意。     

东海北部鲐鲹鱼渔场水文特征的统计学研究

东海北部是鲐鱼主要渔场之一 ,研究其水文及其变化特征对于掌握鲐鱼中心渔场的时空变化规律、指导渔业生产、合理利用海洋渔业资源具有重要意义。根据 1 987— 2 0 0 1年在 2 9°— 32°N、1 2 4 5°E以西海域的海洋环境调查资料和鲐鱼渔场资料 ,在GIS平台上 ,用最优隶属模型划分水团 ,并研究渔场的水团和温、盐跃层特性及其月、年变化之间的相关性 ,用于渔情预报。研究表明 ,用最优隶属模糊聚类方法划分该海域水团的结果与以往的研究结果比较一致 ;鲐鱼渔情与该区域水团第一强度、第二强度之间显示了一定的相关性 ;用稳健统计学方法 ,可确定中心渔场的底层、鱼类栖息水层的温盐范围及其聚类中心值 ;鲐鱼渔情、渔场与水文跃层的关系密切。     

浅海变性水团的软划分

简要介绍了应用模糊聚类方法划分海洋水团的基本原理和步骤;提出了基于欧氏距离的标定公式和用F检验客观地确定水团个数的方法.给出了利用模糊软划分方法划分浅海变性水团的原理和具体步骤.通过计算各测样对每个水团的隶属度,方便且定量地确定出水团核心、边界及混合区.最后给出实例,与黄、东海水团划分的已有研究成果作了比较.     

模糊数学方法在南海北部海区水团分析中的应用

本文将模糊数学的多种方法,用于南海北部海区的水团分析.在用模糊聚类方法划分水团时,提出了基于欧氏距离的相似关系,同时提出了基于F-检验而决定水团个数的方法.以模糊聚类划出的水团为基础,再用软划分方法,对水团边界和测样归属进行合理调整.根据上述结果及区域海洋学的分析,在该海区划出了8个水团:沿岸冲淡水团F、近岸混合水团M、暖表层水团WS、表层水团S、表次层混合水团SU、次层水团U、次中层混合水团UI和中层水团I.将各类水团在-S图解上的点集,归结为变形椭圆凸点集、半无界凸点集和单侧凹点集3种类型.分别提出了建立相应隶属函数的方法,并给出了拟合结果.计算了各季节各水团的熵,讨论了高熵和低熵水团的特征及形成原因.计算了各季节不同水团之间的格贴近度,借以讨论水团变性的特点和它们之间的相互关系.可将8个水团归纳为3种类型:径流冲淡型(F),浅海变性型(M、WS、S和SU),深海大洋型(U、UI和I).     

应用Argo资料分析西北太平洋冬、夏季水团

应用Argo剖面浮标观测的温、盐度资料,分析了西北太平洋海域冬、夏季的温、盐度分布、水团结构及其分布。首先采用T-S点聚图法分析了该海域水团分布的基本情况,由点聚分析结果可知,该海域至少存在6种以上水团;再用模糊聚类软化法对水团作进一步划分,分别计算了该海域6至11类水团的F和△F值,结果表明,冬、夏季的△F值都以划分为8类时为最大,这与大洋水团的稳定性是一致的,因此,该海域冬、夏季水团以划分为8类最佳,它们分别是北太平洋热带表层水、北太平洋次表层水、北太平洋中层水、北太平洋副热带模态水、北太平洋深层水和赤道表层水,以及南太平洋次表层水和南太平洋中层水。     

应用Argo资料分析西北太平洋冬、夏季水团

应用Argo剖面浮标观测的温、盐度资料，分析了西北太平洋海域冬、夏季的温、盐度分布、水团结构及其分布。首先采用T-S点聚图法分析了该海域水团分布的基本情况，由点聚分析结果可知，该海域至少存在6种以上水团；再用模糊聚类软化法对水团作进一步划分，分别计算了该海域6至11类水团的F和△F值，结果表明，冬、夏季的△F值都以划分为8类时为最大，这与大洋水团的稳定性是一致的，因此，该海域冬、夏季水团以划分为8类最佳，它们分别是北太平洋热带表层水、北太平洋次表层水、北太平洋中层水、北太平洋副热带模态水、北太平洋深层水和赤道表层水，以及南太平洋次表层水和南太平洋中层水。     

模糊聚类法在海洋水团划分中的运用初探——Ⅱ.用模糊聚类图与λ集讨论水团个数的辨识及水团间的均匀化过程

在文献[1]中,我们提出了水团模糊聚类划分的理由、原理;并且以1976年10月南海北部某一水域的资料为例,利用模糊聚类的原理作了水团划分的尝试,得到了比较合理的结果。在文献[2]里,我们以文献[1]为基础,建立了水团的模糊子集,运用隶属函数法,研究了如何确定水团的边界位置及混合带(层)的宽(厚)度问题。但是,有关水团个数的确定以及水团间的均匀化过程,上述文献均未具体涉及。有鉴于此,本文进一步假定每一个观测站(层)的海洋水文要素值代表了该测站(层)的小邻域内的海     

象山港海域分区评价方法研究

文章根据2011-2018年在象山港海域调查的象山港水文、水团、水环境、沉积物环境、生物生态等调查数据，将象山港海域划分为若干个具有不同生态变化特征的区域，研究象山港海域内的空间异质性，以便剖析各区域环境的问题。研究发现：象山港水交换特征、水团分布、水环境、沉积环境和生物生态特征将象山港划分为A、B、C、D、E 5个区评价较为合理。该方法可以有效并合理地对象山港海域做出评价，并为相关海洋科学工作者和管理者提供科学依据。     

2014年春季黑潮与邻近海域甲藻组成及其对水团的指示作用

我国东部海域受近岸流、台湾暖流和黑潮的影响,不同水团间环境因子差异较大,甲藻作为初级生产者主要受环境影响,研究分析不同水团浮游甲藻群落组成及分布情况具有重要的生态意义。2014年5-6月,本研究对台湾以东黑潮主流径及东海200m等深线内陆架区进行采样调查,分析测站浮游甲藻的群落结构组成。研究结果表明,网采样品共鉴定出浮游甲藻17属81种,甲藻丰度范围为（0.45-1207.86）×10³cell/m³。根据聚类分析结果,将海区浮游甲藻划分为3个群落类型,分别为受沿岸水团影响的群落Ⅰ、受台湾暖流水团影响的群落Ⅱ和黑潮水团影响的群落Ⅲ。不同水团间甲藻群落结构具有一定差异性,其中甲藻丰度变化趋势为沿岸水团 > 台湾暖流水团 > 黑潮水团,沿岸水团甲藻主要以广温广盐种为主,台湾暖流水团甲藻以广温高盐种为主,黑潮水团甲藻以高温高盐种为主。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

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