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61.
中国海岸带高分辨率遥感系统技术基础研究   总被引:4,自引:4,他引:4  
基于海岸带作为经济高度发展的地带,特别是我国常规海岸带调查已不能满足海岸带经济发展和现代化管理的基本要求,着重从大量高分辨率遥感数据的组织和管理、快速准确的空间定位系统、特征级的影像融合以及海岸带特征提取等算法,共同构成海岸带高分辨率遥感数据处理及分析方法作为系统的技术基础,并通过与此相匹配的海岸带遥感分类系统及其综合制图等方法研究,支撑起海岸带遥感资源调查先进的技术构架,为实现我国海岸带现代化管理奠定理论和技术基础.  相似文献   
62.
The European Regional Seas Ecosystem Model (ERSEM) has been coupled with a two-dimensional depth-averaged transport model of the Humber plume region and run to simulate 1988–1989. Simulations of the spatial and temporal variations in chlorophyll-a, nitrate, phosphate and suspended particulate matter distributions in winter, spring and summer show how the development of the spring bloom and subsequent maintenance of primary production is controlled by the physicochemical environment of the plume zone. Results are also shown for two stations, one characterised by the high nutrient and suspended matter concentrations of the plume and the other by the relatively low nutrient and sediment concentrations of the offshore waters. The modelled net primary production at the plume site was 105 g C m−2 a−1 and 127 g C m−2 a−1 offshore. Primary production was controlled by light limitation between October and March and by the availability of nutrients during the rest of the year. The phytoplankton nutrient demand is met by in-situ recycling processes during the summer. The likely effect of increasing and decreasing anthropogenic riverine inputs of nitrate and phosphate upon ecosystem function was also investigated. Modelling experiments indicate that increasing the nitrogen to silicate ratio in freshwater inputs increased the production of non-siliceous phytoplankton in the plume. The results of this model have been used to calculate the annual and quarterly mass balances describing the usage of inorganic nitrogen, phosphate and silicate within the plume zone for the period of the NERC North Sea survey (September 1988 to October 1989). The modelled Humber plume retains 3.9% of the freshwater dissolved inorganic nitrogen, 2.2% of the freshwater phosphate and 1.3% of the freshwater silicate input over the simulated seasonal cycle. The remainder is transported into the southern North Sea in either dissolved or particulate form. The reliability of these results is discussed.  相似文献   
63.
A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects.  相似文献   
64.
南沙海域万安盆地地质构造特征   总被引:1,自引:3,他引:1  
利用在南沙海域万安盆地所采集的地震、重磁资料及钻井、地质资料,对该盆地的地震反向特征,沉积特征、区域地质、构造特征及构造发展史进行了的简要的论述,本文以该区Tg深度资料为基础,并利用CCOP年刊发表的新生代基底深度资料,初步圈定了万安盆地的边界,并对盆地二级构造单元进行了划分,将盆地划分为5坳3隆、坳隆相间的构造格局。  相似文献   
65.
对福建漳浦前湖湾潮间带两个钻孔岩心和表层沉积物中的有孔虫进行分析研究,有孔虫出现在钻孔最上部厚约2.46-2.96m的砂层中.根据群落优势种生态和非种特征判断,该段各样品有孔虫沉积环境均为近岸浅水环境,尽管其间海面有过3次上下波动变化.根据地层关系判断,其当为现代的产物.  相似文献   
66.
海洋湍流观测技术   总被引:3,自引:0,他引:3  
湍流在海洋能量和水体的交换演化中起着非常重要的作用。海洋湍流研究的发展和海洋湍流观测仪器的研发密切相关。世界上湍流观测仪器的研发起步于上世纪50年代,但是我国在湍流观测设备方面到目前为止仅仅处于起步和引进国外设备阶段。针对我国的情况,文中对海洋湍流观测的平台、探头测量原理及其数据修正、资料后处理等关键技术做一个总结性的介绍,为我国使用引进的海洋湍流设备和自主开发海洋湍流测量设备提供参考。  相似文献   
67.
The short-time-scale variability of the remineralization patterns in the domain of Eastern North Atlantic Central Waters (ENACW) off the NW Iberian Peninsula is studied based on biogeochemical data (oxygen, nutrient salts, total alkalinity, pH, dissolved organic matter and fluorescence of dissolved humic substances) collected weekly between May 2001 and April 2002. The temporal variability of inorganic variables points to an intensification of remineralization during the summer and autumn, with an increase of nutrients, total inorganic carbon and fluorescence and a decrease of oxygen. During the subsequent winter mixing, there is a biogeochemical reset of the system, with lower nutrients, total inorganic carbon and fluorescence and higher oxygen. In contrast to inorganic variables, the levels of dissolved organic matter in the ENACW seem to respond to short-term events probably associated with fast sinking particles, where solubilisation of organic matter prevails over remineralization. Applying a previously published stoichiometric model, we observed a vertical fractionation of organic-matter remineralization. Although there is a preferential remineralization of proteins and P compounds in the entire domain of ENACW, the percentage was higher in the upper ENACW (σ<27.10 kg/m3) than in the lower; the percentage of N and P compounds in the oxidised organic matter was >80% for the upper ENACW and 63% for the lower. Likewise, the redissolution of calcareous structures contributes about 6% and 13% to the carbon regenerated in the upper and lower layers of ENACW, respectively.  相似文献   
68.
大陆岩石圈在张裂和分离时的变形模式   总被引:4,自引:0,他引:4  
通过对南海南北共轭边缘地壳剖面的对比研究,发现大陆岩石圈的物理性质是分层的:上、中地壳呈脆性,下地壳表现出塑性,而岩石圈上地幔则仍呈脆性。因此,在它受张性应力场作用时,其变形和破裂分离方式也是分层进行的:上、中地壳能发生犁式断裂,产生的断块沿断面转动在地表产生一系列半地堑,并使地壳厚度减薄;如拉张应力继续作用时,上、中地壳将沿犁式断裂被拉开,从而形成上、下板块边缘,并彼此分开。下地壳则发生塑性变形,使地壳厚度减薄,并最终将其拉断。岩石圈上地幔亦可产生陡倾断裂,形成的断块沿断面转动亦使其厚度减薄,并最终沿陡倾断裂被拉断。这就是我们称之为岩石圈变形和破裂分 离时的分层变形及分层破裂分离模式。  相似文献   
69.
At pesent,it is very popular to estimate pile bearing capacity by use of empirical formula andphysical indexes of soil provided in the design codes for civil construction in China.This paper attempts toapply mechanical indexes of soil and semi-empirical formulas,which are based on soil mechanical theoriesand were summarized and presented by Meyerhof in 1976,to calculate the axial pile bearing capacity.Lo-ading test results of 24 single piles in Tianjin area have been collected and compared with the proposed cal-ulation approach.  相似文献   
70.
Shear Failure of a Clamped Dented Tubular Beam Under Lateral Impact   总被引:1,自引:0,他引:1  
- The shear failure of a rigid-plastic dented clamped tubular beam under the lateral impact of a mass is investigated. Both the denting and the impact point are in the middle span of the beam. It is assumed that denting does not spread during the shear sliding. Numerical results show that the axial force and lateral deflection of the beam are very small at the moment of the occurence of shear failure, which means that the finite deformation effect can be neglected in the shear failure analysis. Also, some aspects of the initial impact energy are investigated.  相似文献   
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