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111.
112.
通过对我国海域最新的地质地球物理调查资料进行解释分析,并结合近十年来的编图成果,概要论述了研究区的地球物理场以及宏观地质特征,总结了中国海及邻域的宏观构造演化过程。研究表明:中国海及邻域所在的欧亚板块可进一步分为东亚大陆构造域和东亚大陆边缘构造域,地质构造复杂;印支运动结束了古全球构造阶段转而进入新全球构造阶段,从而奠定了中国海及邻域形成演化的基础;古全球构造阶段是由北向南发展,北老南新;新全球构造阶段是由南向北、自西向东发展,南早北晚,西老东新;从古全球构造阶段到新全球构造阶段,不同地区不同块体的发展存在同序时差。  相似文献   
113.
利用一个全球大气环流谱模式,模拟了7月份大气对东半球热带海洋(阿拉伯海、孟加拉湾、南海、西太平洋)海温异常的响应。试验结果表明,热带海洋的热状况是影响亚洲季风环流和降水的一个重要因素。  相似文献   
114.
The expanse of ocean which makes up all marine areas beyond national jurisdiction has been characterized as the last frontier of exploitation on the planet, a figurative final “Wild West”. Existing users of areas beyond national jurisdiction, with the exception of fisheries, currently have a limited footprint there as a consequence, in part, of substantial hurdles in technological development that need to be overcome before many resources can be extracted at a commercially viable scale. However, we argue surprise shifts perpetuated by both established and emerging users could lead to an expansion in actors taking opportunities to chase lucrative resources that they are currently constrained from exploiting. Rapid development could also lead to a “crowded ocean” due to the multiplication of users which could present a problem given the current lack of a unified institutional framework for governance connecting the different user groups. Here, we have collated trends in human use of areas beyond national jurisdiction and offer a framework for, and examples of, unexpected dynamics relevant to living and non-living marine resources. Such an approach is necessary in order to begin to mobilize an adequate governance response to changing conditions and uses of areas beyond national jurisdiction. This governance response must be able to govern established or potential users, be flexible and adaptive in response to unexpected and unpredictable dynamics and be able to transform in the face of unpredictable future uses of this vast area. Here we present a set of institutional design principles as a first tentative step in this direction.  相似文献   
115.
福建三沙湾海洋沉积物中重金属和微量元素的研究   总被引:2,自引:1,他引:2  
蔡清海  杜琦  钱小明 《沉积学报》2007,25(3):456-460
依据2004年的调查资料,分析了三沙湾海洋沉积物中重金属含量的分布,并采用潜在生态危害指数法对其生态危害程度进行了评价。结果表明,沉积物中除Hg和Cd污染较为严重外,其它重金属的生态危害很小。此外,本项目较全面地对三沙湾表层沉积物的微量元素进行了调查研究。  相似文献   
116.
Sand-rich Holocene to modern clastic deposits in the eastern English Channel and the southern North Sea coasts of France and Belgium occur extensively as nearshore-sand bank, estuarine-tidal flat, aeolian dune and beach sub-environments. Sand samples (n = 665) collected from these deposits suggest the presence of three different populations: a largely dominant (83%) medium to fine quartz sand population (“b”), and finer- (14%) and coarser-grained (4%) populations (respectively “c” and “a”). The distribution of these populations among the four sub-environments reflects tide- and storm-dominated sorting and transport processes and a variable degree of mixing. These populations are derived from a mixture of very fine- to very coarse-grained fluvial, outwash and paraglacial sediments deposited on the beds of the eastern English Channel and southern North Sea during the late Pleistocene lowstand. The nearshore-sand bank environment, which also corresponds to the main offshore source area of the coastal deposits, exhibits population heterogeneity reflecting the variability of hydrodynamic conditions and sediment sorting in this zone. The nearshore topography of tidal ridges, banks and troughs in these tidal seas leads to variable bed and tide- and storm-induced shear stress conditions. These conditions only allow for the mobilisation and onshore transport of some of the finer fractions (populations “b” and “c”), leaving an offshore mixture of these finer populations with coarser, less mobilisable sediments (population “a”). Once in the coastal zone, these two finer populations undergo further hydrodynamic sorting and segregation. Variably sorted very fine sands to silts (population “c”) are trapped in the low-energy estuarine-tidal flat sub-environment, while the highly homogeneous population “b” is further sorted in aeolian dune and beach sub-environments. This sorting occurs via a coastal sand transport pathway linking the Somme estuary mouth to the southern North Sea bight where tidal range and wave energy decrease relative to the English Channel. Since this sand transport pathway enables longshore transport of hydrodynamically sorted medium to fine sand derived directly from the immediate nearshore zone, it has further contributed to a net flux of this sand population from the eastern English Channel sea bed to the southern North Sea.  相似文献   
117.
In an attempt to contribute to efforts for a robust and effective numerical tool addressing ship motion in astern seas, this paper presents the development of a coupled non-linear 6-DOF model with frequency dependent coefficients, incorporating memory effects and random waves. A new axes system that allows straightforward combination between seakeeping and manoeuvring, whilst accounting for extreme motions, is proposed. Validation of the numerical model with the results of benchmark tests commissioned by ITTC's Specialist Group on Stability demonstrated qualitative, yet not fully satisfactory agreement between numerical and experimental results in line with other predictive tools. The numerical results indicate that the inclusion of frequency coefficients definitely affects the accuracy of the predictions. In order to enhance further the numerical model and obtain useful information on motion coupling, extensive captive and free running model tests were carried out. Good agreement with the experimental results was achieved. These studies provide convincing evidence of the capability of the developed numerical model to predict the dangerous conditions that a ship could encounter in extreme astern seas. As a result, it could offer new insights towards establishing relationships linking ship behaviour to design, environmental and operational parameters.  相似文献   
118.
福建省三沙湾海洋生态环境质量综合评价   总被引:6,自引:2,他引:6  
三沙湾(由东吾洋、官井洋和三都澳等几个部分组成)位于福建省东北部沿海,四周群山环抱,海岸线曲折,水域辽阔,是个天然良港.三沙湾历史上水质优良,水产资源丰富,是中国著名的大黄鱼产卵场,曾经有许多洄游性经济类鱼虾在这里产卵繁育.但近些年来富营养化问题日趋严重,赤潮时有发生,给三沙湾的环境生态造成了危害.过去对三沙湾的水体和沉积环境虽有研究[1~3],但对其生态环境质量的综合研究尚未见报道.  相似文献   
119.
20多年来,中国海陆及邻域的地质地球物理调查在不断进步,尤其是海域取得很多新认识,但中国海陆及邻域的大范围编图,尤其是大地构造图,没有随之更新;中国海陆的编图还一直存在海陆不接、海域编图相比陆域落后的问题;亟需编制一幅中国海陆及邻域的大地构造图.1992年编制的"中国海域及邻区地质地球物理系列图"的大地构造图,运用以活动论为内涵的全球构造理论作为指导思想,对中国海区及邻域的大地构造特征做出了较好的诠释.最近,中国海陆地质地球物理系列图编制项目,把1:500万中国海陆及邻域大地构造格架图作为图种之一.在全球构造理论基础上发展而来的块体构造学说,作为本次编图的指导思想,根据其大地构造体系,板块和板块边界作为一级构造单元,块体和结合带(缝合带等)作为二级构造单元,结合系列图中重力图、磁力图、地质图等图件成果,以及最近的其他调查研究资料,完善了对特提斯在南海周边的界线、东海陆架的基底构造属性等认识,在研究区内共划分出了欧亚板块、菲律宾海板块和印度—澳大利亚三大板块,6个板块边界构造单元,30个块体、14个结合带和10个缝合带.  相似文献   
120.
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