检索结果-南通市图书馆

Exploration of the Mechanisms for the Low Sensitivity of Deposition Flux to Upstream Sediment Reduction in the North Passage, yangtze estuary

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2023年第4期37卷 533-546页

作者： WANG Xiao-guang ZHANG Wei TONG Chao-feng LEI Zhi-yi QIN Jie JI Xiao-mei HUANG Rui The National Key Laboratory of Water Disaster Prevention Hohai UniversityNanjing 210098China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

Deltas are densely populated industrialized regions,and home to important ports and navigation *** to human interferences,the yangtze estuary has experienced a significant reduction in sediment load caused by the Three Gorges Dam(TGD),as well as adjustment to local morphodynamics by the Deep-water Navigation Channel(DNC).While the dramatic reduction in sediment triggers the increased channel erosion,the deposition flux of the DNC located at the estuary mouth has little *** explore the physical mechanism of this phenomenon,a two-dimensional model is used to establish the relationship between sediment load and the sediment budget of channels based on the bathymetry in *** results show that the tidal reach and the inner estuary have a negative sediment *** the seasonal characteristics of water and sediment fluxes become less obvious *** analysis shows that the influence of upstream sediment load on deposition flux decreases along the channel,with a transition from deposition to erosion occurring in the tidal *** the last-level bifurcation,the annual siltation of sediment in the North Passage(NP)decreases by 4.5%with low *** is attributed to the reduction of sediment load partially mitigated by riverbed erosion and cascade *** addition,the lateral sediment supply,which accounts for 68%of the sediment input in the NP,is ***,this study strengthens the understanding of the relationship between sediment load and artificially deepened systems,thus allowing for better management of estuarine sediment and navigation channel.

关键词： delta navigation channel sediment load erosion and deposition sediment budget yangtze estuary

Extreme storm surge induced coastal inundation in yangtze estuary regions

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第6期31卷 1127-1138页

作者： Zhen-hua Pan Hua Liu Key Laboratory of Hydrodynamics(Ministry of Education) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China DHI China Shanghai 200235China

Coastal inundation induced by the storm surge belongs to one of the major natural hazards in Shanghai and other regions around the yangtze *** worst scenarios of coupling the extreme storm and the sea level rise are presented to assess the storm surge hazard in the yangtze *** numerical model MIKE 21 FM is adopted to implement the numerical study,which includes wind,current,tide and *** storm surge induced by typhoon 9711 is simulated,and the measurements of six tide gauges are used to validate the numerical *** identify the worst case scenario of severe typhoon(9711)and super typhoon(5612),we propose seven typhoon tracks through the yangtze estuary and fourteen scenarios of landfall time for each typhoon track,which generates 196 ***,based on the worst case scenario and the relative sea level rise in the range of 0 m to 0.7 m,the coastal inundation maps of Pudong New District and Changxing Island are provided and discussed.

关键词： Storm surge inundation yangtze estuary sea level rise numerical simulation

Comprehensive analysis on the sediment siltation in the upper reach of the deepwater navigation channel in the yangtze estuary

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2014年第2期26卷 299-308页

作者：匡翠萍陈维顾杰贺露露 College of Civil Engineering Tongji University College of Marine Sciences Shanghai Ocean University

The results from both the field measurements and numerical simulation were reported to comprehensively analyze the sediment siltation in the upper reach of the Deepwater Navigation Channel Project in the yangtze estuary after the project has been implemented. In this research, firstly some basic information about the river evolution in the yangtze estuary is analyzed, including the variations of water depths in the Hengsha Passage and the inlet cross-sections of the North Passage and the South Passage, and changes of diversion ratios of ebb flow and sediment flux in the North Passage and the South Passage, Then the Delfl3D-FLOW model is applied to simulate the hydrodynamics and sediment transport in the yangtze estuary. This model has been calibrated and the simulated results agree well with the measured data of the tidal levels, flow velocities and suspended sediment concentration （SSC）, indicating that the model can well simulate the hydrodynamics and sediment transport of the yangtze estuary caused by the Deepwater Navigation Channel Project. The research results show that the development of the Hengsha Passage and decrease of diversion ratio of ebb flow and sediment flux in the North Passage are the main reasons of sediment siltation in the upper reach of the Deepwater Navigation Channel in the yangtze estuary.

关键词： yangtze estuary Hengsha Passage deepwater navigation channel numerical simulation sediment siltation

Alternate erosion and deposition in the yangtze estuary and the future change

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2020年第1期30卷 145-163页

作者： ZHU Boyuan LI Yitian YUE Yao YANG Yunping LIANG Enhang ZHANG Chuncai BORTHWICK Alistair G.L. School of Hydraulic Engineering Changsha University of Science&TechnologyChangsha 410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha 410114China School of Water Resources and Hydropower Engineering State Key Laboratory of Water Resources and Hydropower Engineering ScienceWuhan UniversityWuhan 430072China Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of TransportTianjin 300456China The Key Laboratory of Water and Sediment Sciences Ministry of EducationCollege of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China School of Engineering The University of EdinburghThe King’s BuildingsEdinburgh EH93JLUK

The morphological changing trend of the yangtze estuary, the largest estuary of Asia, has become a focus of research in recent years. Based on a long series of topographic data from 1950 to 2015, this paper studied the erosion-deposition pattern of the entire yangtze estuary. An alternation between erosion and deposition was found during the past 65 years, which was in correspondence to the alternation between flood and dry periods identified by multi-year average duration days of high-level water flow (defined as discharge ≥ 60,000 m3/s, namely, D≥60,000) from the yangtze River Basin. A quantitative relationship was further developed between the erosional/depositional rate of the yangtze estuary and the interpreting variables of yearly water discharge, D≥60,000 and yearly river sediment load, with contributing rates of 1%, 59% and 40%, respectively. Mechanism behind the alternate erosion and deposition pattern was analyzed by examining residual water surface slope and the corresponding capacity of sediment transport in flood and dry periods. In flood periods, a larger discharge results in steeper slope of residual water level which permits a greater capacity of sediment transport. Therefore, more bed materials can be washed to the sea, leading to erosion of the estuary. In contrast, flatter slope of residual water level occurs in dry periods, and deposition dominates the estuarine area due to the decreased capacity of sediment transport and the increased backwater effect of flood-tide. Coastal dynamics and estuarine engineering projects alter the local morphological changes, but slightly affect the total erosional/depositional rate of the whole estuarine region. Heavy sedimentation within the yangtze estuary after the impoundment of the Three Gorges Dam can be attributed to the reduced occurrence frequency of flood years due to water regulation by the dam, and largely (at least 36%-52%) sourced from the sea. Deposition is still poss

关键词： yangtze estuary erosion and deposition alternation total sediment load evolutional trend

Control System Design and Implementation at Flexible, Distributed Offshore Sensor Test Sites in the yangtze estuary Area

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2021年第2期20卷 285-295页

作者： HU Qingsong JIANG Chao DU Lin LI Jun CHEN Leilei XIANG Peng ZHANG Hongcheng RAHMAN Hafiz Abd ur College of Engineering Science and Technology Shanghai Ocean UniversityShanghai 201306China Anhui Jiyuan Inspection and Testing Technology Co. Ltd.Hefei 230088China

Marine in situ testing is a necessary step for stereotyping newly developed marine sensors. The use of test sites in the yangtze estuary area, which has high turbidity and abundant nutrients, can effectively reduce the needed testing time owing to its harsh conditions. Five test stations were established, and a floating buoy and fixed test equipment were designed. A control system, including a sensor connection, data processor, video remote transmission, and corresponding control algorithm, was developed. The control system enabled the nondestructive monitoring of biological attachments and bidirectional, real-time communication between an upper server on land and the control system at the test sites. The dissolved oxygen(DO), temperature, and pH data of DOS600 and DPS600 sensors were compared with those of AP2000 sensors. Temperature recording using the DOS600 sensor was performed nearly as well as that of the AP2000 sensor. The mean DO values(standard deviations) were 8.414 mg L-1(2.068) and 6.896 mg L-1(1.235) for the DOS600 and AP2000 sensors, respectively, indicating that the DOS600 performance was unsatisfactory. The pH recording of the DPS600 was slightly worse than that of the AP2000 sensor. Experimental results showed that the DO value was more easily affected by the buoy movement of waves compared to the pH and temperature. Moreover, data fluctuations showed that the DO and pH parameters were more vulnerable to biofouling than temperature. Waves and biofouling create a harsh test environment, and the performance difference between the developed sensors and a standard sensor can be obtained in a short time period.

关键词： offshore sensor test sites yangtze estuary control system communication protocol microwave sensor detection data analysis

Impact of water and sediment discharges on subaqueous delta evolution in yangtze estuary from 1950 to 2010

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2014年第3期7卷 331-343页

作者： Yun-ping YANG Yi-tian LI Yong-yang FAN Jun-hong ZHANG Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of Transport State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

In order to determine how the subaqueous delta evolution depends on the water and sediment processes in the yangtze estuary, the amounts of water and sediment discharged into the estuary were studied. The results show that, during the period from 1950 to 2010, there was no significant change in the annual water discharge, and the multi-annual mean water discharge increased in dry seasons and decreased in flood seasons. However, the annual sediment discharge and the multi-annual mean sediment discharge in flood and dry seasons took on a decreasing trend, and the intra-annual distribution of water and sediment discharges tended to be uniform. The evolution process from deposition to erosion occurred at the -10 m and -20 m isobaths of the subaqueous delta. The enhanced annual water and sediment discharges had a silting-up effect on the delta, and the effect of sediment was greater than that of water. Based on data analysis, empirical curves were built to present the relationships between the water and sediment discharges over a year or in dry and flood seasons and the erosion/deposition rates in typical regions of the suhaqueous delta, whose evolution followed the pattern of silting in flood seasons and scouring in dry seasons. Notably, the Three Gorges Dam has changed the distribution processes of water and sediment discharges, and the dam＇s regulating and reserving functions can benefit the subaqueous delta deposition when the annual water and sediment discharges are not affected.

关键词： water discharge sediment discharge, seasonal change delta yangtze estuary

NUMERICAL SIMULATION OF BED TOPOGRAPHY CHANGES INDUCED BY DEEP WATER NAVIGATION CHANNEL PROJECT IN THE yangtze estuary

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第4期15卷 46-53页

作者： ZhangJing-xin LiuHua HeYou-sheng ZhangFu-ran QiDing-man SchoolofCivilEngineeringandMechanics ShanghaiJiaotongUniversityShanghai200030China ResearchCenterofEstuarineandCoastalSciences Shanghai201201China

A study on the mathematical modeling of the two dimensional, time-dependentvariation of bottom topography caused by the spur dikes of the deep water navigation channel projectin the yangtze estuary is reported. The hydro-dynamic flows are computed using the DELFT3D whichserves as the base of computation of sediment transport and bottom deformation. A model of finesediment transport is developed and implemented in an orthogonal curvilinear coordinate system bythe finite difference method. Using the observed water depth of the North Channel of yangtze estuaryfrom 2001 to 2002, the model is calibrated and validated to determine the parameters in thesediment model. The computational results of the changes of the bed in the North Channel induced bythe spur dikes coincide with the measured data except the area near the structures.

关键词： tidal flow sediment transport yangtze estuary mathematical model

Response of nearshore circulation outside yangtze estuary to El Nino events

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2016年第2期9卷 145-154页

作者： Wen-yan Zhang Zheng Gong Chang-kuan Zhang Wei Tan State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing 210098 China CCCC Third Harbor Consultants Co. Ltd. Shanghai 210030 China Jiangsu Key Laboratory of Coast Ocean Resources Development and Environment Security Hohai University Nanjing 210098 China

With consideration of the comprehensive effects of runoff from the yangtze River, East China Sea background circulation, and tidal currents,a regional circulation model, including the yangtze estuary, Hangzhou Bay, and adjacent sea areas was established. The 2002/2003 El Ni^no event was chosen for study of the anomalies of circulation outside the yangtze estuary. The coastal and ocean current systems of the East China Sea and the current structure outside the yangtze estuary were accurately described. The results of vertical circulation analysis basically coincide with those of horizontal circulation analysis, showing that the circulation outside the yangtze estuary is mainly affected by the Taiwan warm current, runoff from the yangtze estuary, and the tide-induced residual current. The El Ni^no event weakens yangtze estuary circulation to a certain degree, and the impacts are more significant in summer than in winter. During the 2002/2003 El Ni^no event, the flux of the Taiwan warm current decreases, and the northward component of the Taiwan warm current decreases by half in February 2003 compared to the previous year. However, its path is relatively stable.

关键词： El Nino Princeton ocean model yangtze estuary Circulation Taiwan warm current

Tidal Level Response to Sea-Level Rise in the yangtze estuary

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2012年第1期26卷 109-122页

作者：龚政张长宽万里明左军成 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University yangtze River estuary Survey Bureau of Hydrology and Water Resource Ministry of Water Resources

The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary. This paper focuses on the variations of tidal level response along the tidal reaches in the yangtze estuary, as well as the impacts of upstream discharge on tidal level response, due to the sea-level rise of the East China Sea. Based on the Topex/Poseidon altimeter data obtained during the period 1993-2005, a stochastic dynamic analysis was performed and a forecast model was run to predict the sea-level rise of the East China Sea. Two- dimensional hydrodynamic numerical models downscaling from the East China Sea to estuarine areas were implemented to analyze the rise of tidal level along the tidal reaches. In response to the sea-level rise, the tidal wave characteristics change slightly in nearshore areas outside the estuaries, involving the tidal range and the duration of flood and ebb tide. The results show that the rise of tidal level in the tidal reaches due to the sea-level rise has upstream decreasing trends. The step between the stations of Zhangjiagang and Shiyiwei divides the tidal reaches into two parts, in which the tidal level response declines slightly. The rise of tidal level is 1-2.5 mm/a in the upper part, and 4-6 mm/a in the lower part. The stations of Jiangyin and Yanglin, as an example of the upper part and the lower part respectively, are extracted to analyze the impacts of upstream discharge on tidal level response to the sea-level rise. The relation between the rise of tidal level and the upstream discharge can be fitted well with a quadratic fimction in the upper part. However, the relation is too complicated to be fitted in the lower part because of the tide dominance. For comparison purposes, hourly tidal level observations at the stations of Xuliujing and Yanglin during the period 1993-2009 are adopted. In order to uniform the influence of upstream discharge on tidal level for a certain

关键词： yangtze estuary sea-level r&e stochastic dynamic analysis and forecast model tidal reaches," dischargeincrement