Understanding the changes of hydrodynamics in estuaries with respect to magnitude of sea level rise is important to understand the changes of transport process. Based on prediction of sea level rise over the 21st cent...Understanding the changes of hydrodynamics in estuaries with respect to magnitude of sea level rise is important to understand the changes of transport process. Based on prediction of sea level rise over the 21st century, the Zhujiang（Pearl River） Estuary was chosen as a prototype to study the responses of the estuary to potential sea level rise. The numerical model results show that the average salt content, saltwater intrusion distance, and stratification will increase as the sea level rises. The changes of these parameters have obvious seasonal variations. The salt content in the Lingdingyang shows more increase in April and October（the transition periods）. The saltwater intrusion distance has larger increase during the low-flow periods than during the highflow periods in the Lingdingyang. The result is just the opposite in Modaomen. The stratification and its increase are larger during the low-flow periods than during the high-flow periods in Lingdingyang. The response results of transport processes to sea level rise demonstrate that：（1） The time of vertical transport has pronounced increase.The increased tidal range and currents would reinforce the vertical mixing, but the increased stratification would weaken the vertical exchange. The impact of stratification changes overwhelms the impact of tidal changes. It would be more difficult for the surface water to reach the bottom.（2） The lengthways estuarine circulation would be strengthened. Both the offshore surface residual current and inshore bottom residual current will be enhanced.The whole meridional resident flow along the transect of the Lingdingyang would be weakened. These phenomena are caused by the decrease of water surface slope（WWS） and the change of static pressure with the increase of water depth under sea level rise.展开更多
One of the most important causes of the freshwater shortage in estuarine area is the increasing seawater intrusion into the river.To simulate seawater intrusion properly,two important factors should be considered.One ...One of the most important causes of the freshwater shortage in estuarine area is the increasing seawater intrusion into the river.To simulate seawater intrusion properly,two important factors should be considered.One is the bidirectional and time-dependent coupling effects between river discharges and tidal forces.The other is the three-dimensional and stratified structure of dynamic processes involved.However,these two factors have rarely been investigated simultaneously,or they were often simplified in previous researches,especially for the estuary connected with an upstream river network through multiple outlets such as the Pearl River Estuary(PRE).In order to consider these two factors,a numerical modeling system,which couples a one-dimensional river network model with a three-dimensional unstructured-grid Finite-Volume Coastal Ocean Model(FVCOM),has been developed and successfully applied to the simulation of seawater intrusion into rivers emptying into the PRE.By treating the river network with a one-dimensional model,computational efficiency has been improved.With coupling 1D and 3D models,the specification of upstream boundary conditions becomes more convenient.Simulated results are compared with field measured data.Good agreement indicates that the modeling system may correctly capture the physical processes of seawater intrusion into rivers.展开更多
本文根据水下地形、遥感影像以及水文观测等资料,综合运用遥感与地理信息系统(geographic information system,GIS)、表层沉积物分析等技术手段,研究了位于我国广东省东部沿海的海湾——长沙湾的动力沉积地貌特征。研究表明,长沙湾湾外...本文根据水下地形、遥感影像以及水文观测等资料,综合运用遥感与地理信息系统(geographic information system,GIS)、表层沉积物分析等技术手段,研究了位于我国广东省东部沿海的海湾——长沙湾的动力沉积地貌特征。研究表明,长沙湾湾外水域涨、落潮流相对较弱,夏季,湾外以自西向东的沿岸流作用为主;冬季,以自东向西的沿岸流作用为主。湾口中东侧涨潮流占优,西侧落潮流占优,湾内涨落潮主流偏向东侧。湾内存在两处表层沉积物输运的汇聚区,分别位于上游黄江河出口右侧近岸和湾中部水域。口门段河道呈现滩淤槽冲的特征,右岸浅滩以及湾中部东侧水域淤积强度相对较大,湾口断面保持基本稳定,地形资料反映的海床淤积区与表层沉积物指示的床沙汇聚区吻合较好。湾顶存在由中段向东、西两侧的输沙过程,导致口门右岸浅滩不断淤积;湾中部是涨、落潮流优势发生转变的区域,泥沙容易落淤,是湾中部淤积的主要原因。上述两处水域发生淤积的原因与该区域表层沉积物指示的床沙输运路径基本一致。广东省东部沿海分布多个湾顶有中小河流入注的海湾,其口门段的动力沉积地貌过程与本研究区域具有一定的相似性。本研究的开展不仅对认识海湾复杂的动力结构及演变规律具有重要理论意义,而且对海湾的环境保护和开发治理具有一定的实际价值。展开更多
基金The National Natural Science Foundation of China under contract No.51409286the Scientific Research Innovation Project of Jiangsu Province Ordinary University Graduate Student under contract No.CXZZ12_0223the Open Fund Project of Zhujiang River Water Resources Commission of the Zhujiang River Water Conservancy Science Research Institute under contract No.[2013]KJ02
文摘Understanding the changes of hydrodynamics in estuaries with respect to magnitude of sea level rise is important to understand the changes of transport process. Based on prediction of sea level rise over the 21st century, the Zhujiang（Pearl River） Estuary was chosen as a prototype to study the responses of the estuary to potential sea level rise. The numerical model results show that the average salt content, saltwater intrusion distance, and stratification will increase as the sea level rises. The changes of these parameters have obvious seasonal variations. The salt content in the Lingdingyang shows more increase in April and October（the transition periods）. The saltwater intrusion distance has larger increase during the low-flow periods than during the highflow periods in the Lingdingyang. The result is just the opposite in Modaomen. The stratification and its increase are larger during the low-flow periods than during the high-flow periods in Lingdingyang. The response results of transport processes to sea level rise demonstrate that：（1） The time of vertical transport has pronounced increase.The increased tidal range and currents would reinforce the vertical mixing, but the increased stratification would weaken the vertical exchange. The impact of stratification changes overwhelms the impact of tidal changes. It would be more difficult for the surface water to reach the bottom.（2） The lengthways estuarine circulation would be strengthened. Both the offshore surface residual current and inshore bottom residual current will be enhanced.The whole meridional resident flow along the transect of the Lingdingyang would be weakened. These phenomena are caused by the decrease of water surface slope（WWS） and the change of static pressure with the increase of water depth under sea level rise.
基金supported by the Non-profit Industry Financial Program from the Ministry of Water Resources of the People’s Republic of China (No 200901032)
文摘One of the most important causes of the freshwater shortage in estuarine area is the increasing seawater intrusion into the river.To simulate seawater intrusion properly,two important factors should be considered.One is the bidirectional and time-dependent coupling effects between river discharges and tidal forces.The other is the three-dimensional and stratified structure of dynamic processes involved.However,these two factors have rarely been investigated simultaneously,or they were often simplified in previous researches,especially for the estuary connected with an upstream river network through multiple outlets such as the Pearl River Estuary(PRE).In order to consider these two factors,a numerical modeling system,which couples a one-dimensional river network model with a three-dimensional unstructured-grid Finite-Volume Coastal Ocean Model(FVCOM),has been developed and successfully applied to the simulation of seawater intrusion into rivers emptying into the PRE.By treating the river network with a one-dimensional model,computational efficiency has been improved.With coupling 1D and 3D models,the specification of upstream boundary conditions becomes more convenient.Simulated results are compared with field measured data.Good agreement indicates that the modeling system may correctly capture the physical processes of seawater intrusion into rivers.
文摘本文根据水下地形、遥感影像以及水文观测等资料,综合运用遥感与地理信息系统(geographic information system,GIS)、表层沉积物分析等技术手段,研究了位于我国广东省东部沿海的海湾——长沙湾的动力沉积地貌特征。研究表明,长沙湾湾外水域涨、落潮流相对较弱,夏季,湾外以自西向东的沿岸流作用为主;冬季,以自东向西的沿岸流作用为主。湾口中东侧涨潮流占优,西侧落潮流占优,湾内涨落潮主流偏向东侧。湾内存在两处表层沉积物输运的汇聚区,分别位于上游黄江河出口右侧近岸和湾中部水域。口门段河道呈现滩淤槽冲的特征,右岸浅滩以及湾中部东侧水域淤积强度相对较大,湾口断面保持基本稳定,地形资料反映的海床淤积区与表层沉积物指示的床沙汇聚区吻合较好。湾顶存在由中段向东、西两侧的输沙过程,导致口门右岸浅滩不断淤积;湾中部是涨、落潮流优势发生转变的区域,泥沙容易落淤,是湾中部淤积的主要原因。上述两处水域发生淤积的原因与该区域表层沉积物指示的床沙输运路径基本一致。广东省东部沿海分布多个湾顶有中小河流入注的海湾,其口门段的动力沉积地貌过程与本研究区域具有一定的相似性。本研究的开展不仅对认识海湾复杂的动力结构及演变规律具有重要理论意义,而且对海湾的环境保护和开发治理具有一定的实际价值。
