Two-Dimensional Mathematical Model of Tidal Current and Sediment for Oujiang Estuary and Wenzhou Bay   总被引：3，自引：0，他引：3  

陆永军  李浩麟  董壮  陆建宇  郝嘉凌 《中国海洋工程》2002,(1)

A 2-D mathematical model of tidal current and sediment has been developed for the Oujiang Estuary and the Wenzhou Bay. This model accomodates complicated features including multiple islands, existence of turbidity, and significant differ-ence in size distribution of bed material. The governing equations for non-uniform suspended load and bed load transport are presented in a boundary-fitted orthogonal curvilinear coordinate system. The numerical solution procedures along with their initial conditions, boundary conditions, and movable boundary technique are presented. Strategies for computation of the critical condition of deposition or erosion, sediment transport capacity, non-uniform bed load discharge, etc. are suggested. The model verification computation shows that, the tidal levels computed from the model are in good agreement with the field data at the 18 tidal gauge stations. The computed velocities and flow directions also agree well with the values measured along the totally 52 synchronously ob  相似文献   

Analysis on Suspended Sediment Deposition Rate for Muddy Coast of Reclaimed Land   总被引：3，自引：0，他引：3  

WANG  Yigang 《中国海洋工程》2001,(1):147-153

A new expression for calculating suspended fine-sediment deposition rate is developed based on theoretic analysis and experiments. The resulting equation is applied to simulation of fine sediment deposition in the reclaimed land in the Hangzhou Bay, China. The hydrodynamic environment in this area is solved by use of a long wave model, which gives the 2D-velocity field and considers bathymetric changes due to fine sediment deposition. The expression is proved convenient to use in engineering practice, and the predicted deposition rate agrees with the annual data available from field measurements from the first year to the third year after the construction of the long groin as a reclaiming method.  相似文献   

潮间带水沙多层位同步测量系统应用的初步研究   总被引：2，自引：0，他引：2  

王爱军  汪亚平  柯贤坤  李占海 《海洋通报》2003,22(3):61-68

利用水压、光电转换原理研制成的多层位水沙同步测量系统(WCT系统)不仅可测量潮间带水位随时间的变化系列、同一层位的浊度及流速，还可以同步观测这些参数在潮间带水流剖面不同层位上的变化。野外对比试验表明，WCT系统获得的流速值与直读式流速仪的测量结果基本一致，平均相对误差为14．52％；悬沙传感器经野外现场率定获得悬沙浓度，平均相对误差为21．96％，精度比室内率定提高—倍以上。悬沙粒径是影响悬沙浓度测量精度的主要因素。此外，自然环境(如海水温盐度)的变化及仪器本身的特性也可能影响到测量结果。因此，WCT系统在潮间带的水位、流速和悬沙浓度的观测和边界层研究方面有相当潜力。  相似文献   

三门湾悬移质输运特征   总被引：1，自引：0，他引：1  

杨士瑛  陈波 《海洋湖沼通报》2007,24(4):21-29

三门湾为一典型半封闭强潮海湾,平均潮差4.25m,湾内外水沙交换剧烈。根据2003年在三门湾水文泥沙测验、分析结果,湾口附近N1、N2、N3站所构成的断面上:(1)从大潮到小潮,流速递减;从N1站向N3站流速增加;春季,大多数情况下涨潮流速大于落潮流速。而秋季,大多数情况下涨潮流速小于落潮流速。(2)春、秋季,大小潮期间N1、N2、N3三个站上平均悬移质浓度都是涨潮大于落潮;中潮期间这三个站上平均悬移质浓度都是涨潮小于落潮。  相似文献   

珠江口悬浮泥沙迁移数值模拟   总被引：13，自引：1，他引：13       下载免费PDF全文

陈晓宏  陈永勤  赖国友 《海洋学报》2003,25(2):120-127

建立了珠江口海域三维悬浮泥沙的非饱和输沙数学模型,并与珠江口三维水动力斜压模型耦合,对悬沙迁移分布进行了模拟。模型由4个点的逐时实测含沙量过程进行了验证。各点模拟含沙量与实测含沙量吻合较好,表层分布与同期珠江口悬沙分布遥感图像基本一致.模拟结果表明,珠江口海域悬沙分布分层明显,河口附近水域大多为底层含沙量大于表层,但在盐淡水交汇处出现中层含沙量最小的情况总体上,自各个口门输出的泥沙受沿岸流作用向西南万向输送明显。大多数河口落潮时相对涨潮时含沙量等值线外移,反映珠江口水域悬浮泥沙主要来自河流。  相似文献   

Temporal Variations of Nutrients, ­Chlorophyll a and Particulate Matter in Three Coastal Lagoons of Amvrakikos Gulf (Ionian Sea, Greece)     

Konstantinos A. Kormas  Artemis Nicolaidou  & Sofia Reizopoulou 《Marine Ecology》2001,22(3):201-213

Abstract. The temporal variations of nutrients, chlorophyll a (chl a ), suspended particulate matter (SPM) and particulate organic carbon (POC) were measured over 12 months in three shallow coastal brackish water lagoons of the Amvrakikos Gulf, Ionian Sea. Two of the lagoons, Tsoukalio and Rodia, are interconnected but separated from Logarou by a narrow strip of land. Logarou has a better water exchange with the sea as indicated by the higher salinity and dissolved oxygen concentrations and the smaller variation of the above-mentioned parameters. Nitrate concentrations were largely the same in the three lagoons and higher than in the Amvrakikos Gulf. Phosphate concentrations in Logarou exceeded by far those of Tsoukalio/Rodia; the increased phosphate levels recorded in January caused an extended phytoplankton bloom with chl a concentrations higher than in the other two lagoons. Chl a in Tsoukalio was positively correlated with nitrate whereas in the most shallow lagoon, Logarou, it showed a positive correlation with light winds (force 4 and lower), probably caused by resuspension from the sediment. Increased phytoplankton biomass in Logarou coupled with the better water exchange may be related to the higher fish production in this lagoon.  相似文献   

The use of sediment traps in high-energy environments     

J. White 《Marine Geophysical Researches》1990,12(1-2):145-152

A sediment trap is a container deployed in the water column with the aim of providing a representative sample of the material settling through that water column before it passes to a greater depth and ultimately to the seabed or lake bottom. A review of the previous literature shows cylinders and baffled funnels to be the most efficient sediment trap design in flows less than 0.1 m/s. For flow velocities above 0.1 m/s recent evidence suggests upwelling from the trap base, and possible undercollection. The degree of undercollection depends on the flow velocity, the type of trap, the height: diameter (aspect) ratio of the trap, and the type of sediment. Recent experiments suggest that cylinders with an aspect ratio of 3 may be efficient collectors in velocities up to 0.2 m/s. The use of cylinders is not recommended in velocities above 0.2 m/s. For unbaffled asymmetric funnels a lower limit of 0.12 m/s is suggested.  相似文献   

基于GF-1影像的洞庭湖区水体水质遥感监测   总被引：1，自引：0，他引：1  

彭保发  陈哲夫  李建辉  罗望军  甘洁  曾荣亮 《地理研究》2018,37(9):1683-1691

湖泊水质监测是有效开展湖泊水环境综合管理与水污染防治实施的基础,也是湖泊藻华风险评估与生态安全建设的重要依据。本文基于GF-1号影像对2014-2016年洞庭湖水体的叶绿素a浓度、悬浮物浓度和透明度展开遥感监测,结果表明：叶绿素a主要集中在水流速度较慢的安乐湖、大小西湖和东洞庭湖西部地区,其他区域水体扰动力大,叶绿素含量a较低。透明度从北到南递增,与悬浮物浓度的分布趋势相反,符合常规监测规律。东洞庭湖水质较南洞庭湖和西洞庭湖差,水污染程度处于全湖最高水平。GF-1数据可精确反映叶绿素a浓度、悬浮物浓度和透明度指数的空间变化规律,也为后续高分遥感影像湖泊水质监测的应用研究提供了重要参考。  相似文献   

Developing water quality retrieval models with in situ hyperspectral data in Poyang Lake,China     

Fangyuan Chen  Di Xiao  Zhuochao Li 《地球空间信息科学学报》2016,19(4):255-266

Applying remote sensing techniques to develop the retrieval models and further to obtain the spatiotemporal information of water quality parameters is necessary for understanding, managing, and protecting lake ecosystems. This study aimed to calibrate and validate the retrieval models for estimating the concentrations of chlorophyll a (C_CHL), suspended particulate matter (C_SPM), and dissolved organic carbon (C_DOC) with the in situ hyperspectral measurements in Poyang Lake, China in 2010 and 2011. The model calibration and validation results indicated that: (1) for C_CHL retrieval, significantly strong and moderate correlations existed between the measured and estimated values (with the correlation coefficient r = 0.92 and r = 0.76) using the exponential model and the three-band model, respectively, with biased estimation observed for the exponential model; (2) for retrieving C_SPM, there was a strong correlation between the measured and estimated values (r = 0.95) using the exponential model; and (3) no significant correlation between measured and estimated C_DOC values was found with our developed models. More work is needed to allow the water quality of Poyang Lake to be accurately and steadily estimated, especially for C_CHL and C_DOC.  相似文献   

Floodplain sedimentation: Quantities,patterns and processes     

Nathalie E. M. Asselman  Hans Middelkoop 《地球表面变化过程与地形》1995,20(6):481-499

This paper presents the result of measurements of floodplain sedimentation using sediment traps. The study was carried out on two embanked floodplains along the Rivers Rhine and Meuse in The Netherlands during a 3 day flood in January 1993. Raster maps of sediment accumulation were made by interpolating the measurements from the traps using block kriging. The sediment maps show clear patterns in sediment accumulation, together with the estimated interpolation errors. Average sediment accumulation ranges between 0·57 and 1·0 kg m^?2. High sediment accumulation is found on the levees (4 kg m^?2 or more) and on low lying areas (1·6 kg m^?2); sediment accumulation decreases with distance from the main channel. The sedimentation patterns are related to floodplain topography and sediment transporting mechanisms. Sediment transport by turbulent diffusion as well as by convection can be recognized. Also, flood duration and the process of sediment settling out in ponding water in closed depressions are important. The applied method allows comparison of the results with raster-based sedimentation models.  相似文献