Temporal and spatial changes of dunes in the Changjiang (Yangtze) estuary,China     

Li Weihua  He-Qin Cheng  Li Jiufa  Dong Ping 《Estuarine, Coastal and Shelf Science》2008

The response of subaqueous dunes to the variation of riverine sediment supply in an estuary is rarely reported. Five sets of field measurements of bed sediments and topography were made in the Changjiang estuary, China during dry and flood seasons for the past 9 years. Results show that dunes were mainly three-dimensional (3D) during flood seasons and two-dimensional (2D) dunes during dry seasons. Dunes were also much larger in flood seasons. Dunes mainly occurred within the main channels of the estuary although they extended 11.7 km seaward of their normal extent in the South Channel during dry seasons from 2002 to 2006. This extension of the dune field is likely due to a sharp decline of sediment discharge caused by large reservoirs such as Three Gorges.  相似文献   

遥感信息协同智能网格模型设计及实现   总被引：1，自引：1，他引：0  

孙杰  马洪超  钟良 《测绘科学技术学报》2009,26(4)

为了给普通用户提供一个自动化、智能化的遥感信息处理平台,以OGSA(Open Grid Services Architecture) 为基础,结合多智能体技术,提出了基于协同智能网格的遥感信息处理模型RSCIG(Remote Sensing Cooperative Intelligent Grid);设计了RSCIG的体系结构,详述了如何高效准确地协同现有的网格服务以完成所面临的任务;实现了一个RSCIG体系结构下的遥感信息处理原型系统.  相似文献   

Distribution characteristics of heavy metals in surface sediments and core sediments of the Shenzhen Bay in Guangdong Province, China   总被引：1，自引：1，他引：0  

ZUO Ping  WANG Yaping  MIN Fengyang  CHENG Jun 《海洋学报(英文版)》2009,28(6):53-60

The concentration of zinc, chromium, cadmium, nickel, lead and copper was measured on both surface sediments and core sediments in the Shenzhen Bay. The average contents of all metals have exceeded the background values in the coastal zone of Guangdong Province. Cadmium is a heavy pollution matter which indicates a strong pollution level according to the ecological risk coefficient method. The ecological risk index of the whole area is 299 which belongs to middle and strong level. The area with strong pollution level is the near shore area closing to the inside of Shenzhen Bay, Shakou area is in the middle level while the weak pollution level occurs in Shenzhenhe Estuary according to ecological risk index. The four sediment cores can be divided into two parts based on lead-210 dating, sediments size analysis and economic development period in surrounding areas since 1950 with strong human intervention. The sediment size, deposition rate and human activities have positive relationship with the contents of heavy metals which directly impact the pollution level of heavy metals in sediments in Shenzhen Bay.  相似文献   

Analyses of the long-term salinity variability in the Bohai Sea and the northern Huanghai(Yellow) Sea     

YUHuaming  BAOXianwen  L&#;Cuilan  CHENXu''en  KUANGLiang 《海洋学报(英文版)》2009,28(5):1-8

Based on the comprehensive collection of the field observed salinity of the Bohai Sea (BHS) and the northern Huanghai Sea (NHS) from the 1950s to the present,the patterns of 10-years-averaged salinity at the different layers in the recent five decades (the 1950s,the 1960s,the 1970s,the 1980s and the 1990s) are obtained by the spatial-temporal interpolation technique with the scrupulous data quality control in this study.Then,by combining the spatial-temporal interpolation technique with successive correction method,the annual distributions of salinity both in the BHS and in the NHS are obtained as well.The data analyses indicate that the overall salinity in the BHS and the NHS increases from the 1960s till the present,with the increase of annual mean salinity of 0.04 psu from the 1950s,and the maximum increase rate of salinity is about 0.14 psu/a in the Bohai Bay.The high salinity tongue extended significantly from the NHS into the BHS.The intensified eastern wind field is related to the western intrusion of the NHS warm current,which probably leads to the moving forward of the high salinity water mass into the BHS.However,it is rather different from the salinity distribution characteristics between the 1950s and the 1960s.The extensive precipitation in the 1960s could lead to an increase in the discharge of the Huanghe River,which might result in the decrease of salinity in the BHS.But the salinity isoline of 32 in the NHS still extended significantly into the BHS in the 1960s.Since the 1980s,the patterns of salinity distribution have changed thoroughly.The salinity in the central area of the BHS was low,while the salinity in the Bohai Bay and the Liaodong Bay was higher than the other regions with its horizontal salinity gradient decreasing in the 1980s.The Empirical Orthogonal Function Analysis (EOF) is also conducted to study the interannual salinity variability of the BHS and the NHS.The correlation coefficient between the time coefficient series of the main mode and the Huanghe River discharge can reach -64.57%.It can be concluded that salinity variation of the BHS and the NHS has strong negative correlation with the Huanghe River discharge.  相似文献   

BTEX anomalies used as indicators of submarine oil and gas reservoirs   总被引：1，自引：0，他引：1  

ZHANG Yong  MENG Xiangjun  SUN Ping  CHEN Yanli  QU Peng 《海洋学报(英文版)》2009,28(4):50-56

It is a conventional method for petroleum prospecting to generally use paraffin hydrocarbon as basic indexes of oil and gas. This conventional geochemical technology, however, shows some limits in the prospecting as paraffin is vulnerable to influences from human and biologic activities. Consequently, BTEX (short for benzene, toluene, ethyl benzene and xylem, which are direct biomarkers) among aromatic hydrocarbon series has been taken into account for the oil and gas prediction. Domestic and foreign study results demonstrate that BTEX is hardly disturbed and can well indicate oil and gas reservoirs. Based on measured data from a South China Sea area, the present authors have used self-developed visual assessment software for petroleum prospecting has been used to process data, strip background anomalies, and outline significant BTEX anomalies. By comparison with stratigraphic profiles of the target area, it is confirmed that BTEX is a good indication of marine oil and gas during the petroleum prospecting.  相似文献   

Three-dimensional scour below offshore pipelines in steady currents     

Liang Cheng  Kervin Yeow  Zhipeng Zhang  Bin Teng 《Coastal Engineering》2009,56(5-6):577-590

This paper presents the results of an experimental investigation on three-dimensional scour below offshore pipelines subject to steady currents. The major emphasis of the investigation is on the scour propagation velocity along the pipeline after the scour initiation. Physical experiments were conducted to quantify the effects of various parameters on scour propagation velocity along the pipeline in a water flume of 4 m wide, 2.5 m deep and 50 m long. Local scour depths directly below the model pipeline were measured using specifically developed conductivity scour probes. Effects of various parameters such as pipeline embedment depth, incoming flow Shields parameter and flow incident angle (relative to the pipeline) on scour propagation velocity along the pipeline were investigated. It was found that scour propagation velocity generally increases with the increase of Shields parameter but decreases with the increase of the pipeline embedment depth. A general predictive formula for scour propagation velocity is proposed and validated against the experimental results.  相似文献   

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郑水明  王岚  黄江  王平 《大地测量与地球动力学》2008,28(6):73-76

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济南张夏组灰岩岩溶地下水供水潜力探讨   总被引：1，自引：1，他引：0       下载免费PDF全文

韩祥银  韩亮  付春升  方庆海  王集宁  刘广哲 《山东国土资源》2008,24(12)

济南南部广布巨厚张夏组灰岩,其中赋存优质丰富的岩溶地下水。出露众多泉水,其流量为800～8000m3/d。该文通过简述济南地区张夏组灰岩岩溶地下水的赋存条件与水文地质特征,概略计算与评价其资源量,论证开发利用这一新水源的可行性,以期为济南供水与保泉开辟新途径。  相似文献   

野外型断层活动连续监测系统     

徐春阳  杨江  高平  邓涛  杜为民  吕宠吾 《大地测量与地球动力学》2009,29(Z1):120-121

介绍野外型断层活动连续监测系统的组成、布设及主要技术指标。  相似文献   

基于Voronoi图的人口普查区的划分技术研究   总被引：1，自引：0，他引：1  

冯亮  刘德钦  马维军 《测绘科学》2009,34(2)

人口普查区的划分是进行人口普查的先期工作。本文探讨了利用Voronoi图的良好空间拓扑属性进行人口普查区划分的方法。文章从多边形数据出发,利用间接法实现Voronoi图的生成,然后根据普查区划分的人口阀值,通过相邻Voronoi图之间的操作,最终实现人口普查区的划分。可为人口普查提供有效的服务,并间接地为人口空间化提供了一种有效的表现形式。  相似文献