ArcSDE下的地下管线数据组织

数据组织是地下管线数据建库工作中最核心的基础工作。由于稳定和高性能,武汉市开展使用了空间数据中间件ArcSDE,依据GeoDatabase数据模型标准,制定了兼容性强的、独创的数据结构,实现了地下管线数据高效组织和安全利用。     

基于GIS的海域管理信息系统建设

海域作为重要的自然资源,是海洋经济发展的基础和载体。开展海域管理信息系统建设,是实现海域信息资源共享和海域信息社会化服务的重要基础。本文重点论述了应用GIS技术进行海域管理信息系统建设的思路、功能设计和关键技术,包括基于矢量数据的建库系统,基于工作流技术的日常海域管理系统等。     

海洋空间数据库的建立和发展

空间数据是按照可持续发展原则进行资源管理和进行决策的信息基础。许多国家正在建立和发展海洋空间数据库,以促进数据资料的获得和分享。海洋和海岸管理活动需要空间数据的支持,海洋空间数据库的建立为此提供了条件。利用海洋空间数据对海洋和海岸进行有效管理的重要性已引起国际社会的关注。     

利用ACCESS建立地理信息库的实践

本文简要介绍了地理信息的特点及以ACCESS为代表的新一代关系数据库的特点。探讨了利用ACCESS建立地理信息库的方法。认为其最大优点就是可以有效地解决地理信息中的属性数据和空间数据的“无缝”结合问题,从而使复杂的地理空间数据的维护变得十分简单容易。     

全国海岛资源综合调查数据库系统的设计

本文叙述了全国海岛资源综合调查数据库系统的设计思想、系统的目标、设计的主要步骤以及系统的内容。整个系统由五部分组成:总控、录入建库系统、调查数据库、数据字典库、检索、查询服务系统。对系统设计过程中出现的一些技术问题,提出了解决的方法。最后,提出了数据库建设中应注意的问题。     

基于数据库的地形图制图研究

GIS数据和制图数据之间的差异是基于GIS数据库实现地图制图输出的难点。分析了当前基础地理信息数据建库的情况及其适用于基本比例尺制图的特点,充分利用了ArcGIS提供的地图表现功能,探讨了ArcGIS环境下基于Geodatabase数据库实现基本比例尺地形图制图的方法,并采用ArcObjects作为二次开发的平台,设计开发了基于GIS数据库的基本比例尺地形图制图模块。     

广西海岸带生物多样性信息管理系统的构建

根据广西海岸带生物多样性保护和信息管理工作的需要,通过整合历史调查资料及大量的现状调查,应用GIS技术和计算机技术等,将广西海岸带生物多样性的空间分布、生长状况和历史演变趋势等信息集成于一体,设计研建本系统,系统功能包括空间数据编辑、空间数据查询、空间数据分析、数据输出和专家知识库等,具有较好的集成性、实用性与应用前景,为广西海岸带生物多样性保护管理提供决策支持。     

美国海洋测绘数据的共享和管理及对我国的启示

海洋测绘数据是实施海洋各项研究和开发活动不可或缺的基础资料,以几类主要海洋测绘数据为目标,介绍了美国 海洋机构共享的海洋测绘数据的基本情况,在此基础上,以NOAA的NGDC为例,介绍并分析了其主要的空间数据管理方法 和模式,旨在为我国海洋测绘数据的共享和服务平台建设提供借鉴和参考。     

空间数据仓库元数据系统的研究与设计

介绍了空间数据仓库元数据的概念、功能及元数据系统的组成要素，重点研究了空间数据仓库元数据系统的设计，提出了邦联式与客户机／服务器、浏览器／服务器相结合的系统结构设计方案，并进一步设计了空间数据仓库元数据系统的功能和元数据库信息模型。该系统研究与设计的目的是为了较好地解决空间数据仓库中海量数据的管理、共享及互操作等问题。     

地理信息系统的坐标系定义

坐标系是空间数据的基准，也是地理信息系统的基础，定义正确的坐标系对空间数据的使用、显示、分析、拼接、成图以及标准化管理至关重要。以Mapinfo公司的组件式开发工具MapX为例阐述了地理信息系统中的坐标系定义与转换方法。     

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.     

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.     

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.     

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.     

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。     

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

<正>~~