钦州湾潮流特征分析   总被引：9，自引：0，他引：9  

邱绍芳  侍茂崇  陈波 《海洋通报》2003,22(3):9-14

根据1994年5月和11—12月两个航次的调查及近年有关海湾的海流观测资料，分析了钦州湾的潮流特征，观测资料来自分布于该海湾东中西三个航道及相关区域的8个测站。钦州湾涨落潮流特征：落潮流速大于涨潮流速：东部最大涨落潮流速小于西部：夏季落潮流总是大于冬季：龙门水道附近的流速最大，而其余区域的流速相对较小。外湾(钦州湾)余流，是气旋式环流：水体东进而西出。从湾内来的泥沙和污染物质，主要从西部进入外海；中、东槽是主要“进水”通道，外海低泥沙含量、少污染物质的清洁水从这里潮流而上。因此，与西部相比，东部盐度高，水质清洁，底质重金属含量少。  相似文献   

Coastal Upwelling Activity on the Pacific Shelf of the Baja California Peninsula     

Oleg Zaytsev  Rafael Cervantes-Duarte  Orzo Montante  Artemio Gallegos-Garcia 《Journal of Oceanography》2003,59(4):489-502

High primary productivity on the Pacific coast of the Baja California Peninsula is usually related to coastal upwelling activity that injects nutrients into the euphotic zone in response to prevailing longshore winds (from the northwest to north). The upwelling process has maximum intensity from April to June, with the coastal upwelling index varying from 50 to 300 m³/s per 100 m of coastline. Along the entire coast of the peninsula, the upwelling intensity changes in accordance with local wind conditions and bottom topography. Spatial variability can also be modulated by the influence of mesoscale meanders of the California Current. We have identified the seasonal and synoptic variability of upwelling signatures on the Baja California shelf, using averaged monthly and weekly sea surface temperature (SST) distributions obtained from remote sensing imagery from the Advanced Very High Resolution Radiometer in the period from 1996 to 2001. Analysis of SST distribution and direct experimental data on temperature and nutrient concentration shows that the areas with the coldest SST anomalies were closely related to the bottom slope, shelf width, and coastline orientation relating to wind direction. We also assume that the nutrient transport into the coastal lagoons may be forced by the coupling of coastal upwelling and tidal pumping of surface waters into the lagoon system. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Modeling bed-load transport of coarse sediments in the Great Bay Estuary, New Hampshire   总被引：1，自引：0，他引：1  

A. Bilgili  M. R. Swift  D. R. Lynch  J. T. C. Ip 《Estuarine, Coastal and Shelf Science》2003,58(4):937-950

Current, sea level and bed-load transport are investigated in the Lower Piscataqua River section of the Great Bay Estuary, New Hampshire, USA—a well-mixed and geometrically complex system with low freshwater input, having main channel tidal currents ranging between 0.5 and 2 m s⁻¹. Current and sea level forced by the M₂M₄M₆ tides at the estuarine mouth are simulated by a vertically averaged, non-linear, time-stepping finite element model. The hydrodynamic model uses a fixed boundary computational domain and accounts for flooding–drying of tidal flats by making use of a groundwater component. Inertia terms are neglected in comparison with pressure gradient and bottom friction terms, which is consistent with the observed principal dynamic balance for this section of the system. The accuracy of hydrodynamic predictions in the study area is demonstrated by comparison with four tidal elevation stations and two cross-section averaged current measurements. Simulated current is then used to model bed-load transport in the vicinity of a rapidly growing shoal located in the main channel of the lower system. Consisting of coarse sand and gravel, the shoal must be dredged every five to eight years. Two approaches are taken—an Eulerian parametric method in which nodal bed-load flux vectors are averaged over the tidal cycle and a Lagrangian particle tracking approach in which a finite number of sediment particles are released and tracked. Both methods yield pathways and accumulations in agreement with the observed shoal formation and the long-term rate of sediment accumulation in the shoal area.  相似文献   

A Computational Model for Velocity Separation in Shallow Sea   总被引：1，自引：0，他引：1  

SONG  Zhiyao 《中国海洋工程》2002,16(3):407-413

Based on the hydrodynamical feature and the theoretical velocity profiles of tidal flow and vvind-induced flow in shal-low sea, a computational model is established for the first time, which can separate observed velocity into tidal velocity and wind-induced velocity by use of the least square method. With the model, not only the surface velocities of tidal flow and vvind-induced flow are obtained, but also the bed roughness height is determined and the wind velocity above the wa-ter surface is estimated. For verification of the model, the observed velocity in the Yellow River Estuary and the laborato-ry test is separated, then it is applied to the Yangtze River Estuary. All the results are satisfactory. The research results show that the model is simple in method, feasible in process and reasonable in result. The model is a valid approach to analysis and computation of field dala, and can be applied to separate the observed velocity in shallow sea; at the same time, reasonable boundary conditions of th  相似文献   

A computer simulation model for predicting rates and scales of movement of demersal fish on the European continental shelf   总被引：1，自引：1，他引：1  

Arnold  G. P.; Holford  B. H. 《ICES Journal of Marine Science》1995,52(6):981-990

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北部湾三维潮流场数值研究(英文)     

刘学刚  叶安乐 《中国海洋大学学报(自然科学版)》1988,(4)

本文对北部湾三维潮波进行了数值研究,并将所得结果与现有观测资料作了比较。通过比较发现两者相当一致。文中还绘制了M_2和K_1分潮的同潮图,并对其作了讨论。可以断定,北部湾的日潮优势是由日潮共振所引起的。M_2和K_1分潮流的水平分布表明,强流区位于它们各自的蜕化无潮点附近。还讨论了分潮流的铅直结构,可以看出这种结构十分接近实际分潮流场的特征。  相似文献   

分潮波模型多资料数值计算方法研究　Ⅱ.有限差分最小二乘方法     

潘文波  孙文心  王骥 《中国海洋大学学报(自然科学版)》1996,(2)

对含多资料的分潮波模型的超定问题进行探讨，建立一种有限差分—最小二乘方法，该方法使得岸边资料直接进入了计算方程，并保证岸界法向流速为零条件。通过对渤海的四大分潮的试算，证实本方法可行。  相似文献   

ECOMSED模式在杭州湾海域流场模拟中的应用   总被引：13，自引：0，他引：13       下载免费PDF全文

堵盘军  胡克林  孔亚珍  丁平兴 《海洋学报》2007,29(1):7-16

针对杭州湾独特的喇叭型强潮河口湾的特点,基于Blumberg等(1996)的ECOMSED模式,引入动边界技术,建立杭州湾三维动边界的潮流模型.模型以正交曲线坐标下三维非线性水动力方程为基本方程,应用Mellor和Yamada的2.5阶湍流闭合模型计算紊动黏滞系数,嵌入Grant和Madsen的底边界层模型考虑波浪对底部应力的作用,采用干湿网格法模拟潮流漫滩过程;综合考虑径流,风应力,密度流和M₂,S₂,K₁,O₁四个主要分潮和M₄,S₄,MS₄三个浅水分潮的作用,从而提高杭州湾潮流模拟的精度.通过验潮站调和常数和多次海流连续观测资料的验证,表明该文建立的模型可以更好的用于杭州湾流场的预报模拟.  相似文献   

潟湖潮汐通道水力特性与治理     

田向平  李春初 《海洋通报》2006,25(4):9-15,62

综合论述了潟湖潮汐通道口门之流速、断面面积、通道长度、延时角和饱满系数之间的关系,以及沿岸漂沙对口门的影响。对不同类型的潟湖潮汐通道,提出了中潮位射流导流堤、口门复式断面和通道分汊等治理方法及其通道口门相关尺度的具体计算。  相似文献   

Factors involved in growth plasticity of cockles Cerastoderma edule (L.), identified by field survey and transplant experiments     

Xavier De Montaudouin 《Journal of Sea Research》1996,36(3-4)

In Arcachon Bay, a macrotidal coastal lagoon in southwest France, growth rates of cockles Cerastoderma edule (L.) differ greatly between locations. Sampling of populations at different tidal levels showed that the mean shell length was significantly and positively correlated with immersion time, whereas no correlation was found with population density and microphytobenthos biomass. Transplants of cockles between two intertidal sites were used to examine the relative importance of habitat and site of origin for growth rate and condition index. Artifacts due to manipulation were assessed, i.e. the impact of enclosures on growth, conditon index and mortality. During a 5-mo reciprocal transplant experiment, growth rates of the transplanted cockles and the cockles already present were similar, whereas the sites of origin did not affect growth rate. Condition index, however, displayed significant differences in relation to both transplant and origin sites. During a further 6-mo experiment in which cockles were transplanted from one site to four new sites, growth was mainly influenced by tidal level. These results indicate that net growth started when cockles were immersed 30% of the time. It is concluded that, on the scale of Arcachon Bay (156 km²), differences in growth and condition between cockle populations are largely phenotypic. Tidal level (i.e. food supply and emersion stress) accounts for most of these differences, but the existence of genetically or physiologically different populations cannot be excluded.  相似文献