As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for stud...As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.展开更多
In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction fun...In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction functions are supposed to be the solving conditions. Next, the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series. Finally, the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.展开更多
To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerg...To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerged configuration is used to reduce wave forcing and to avoid contact with floating ice during winters in northern waters. Each raft consists of three pontoons connected by a grid framework. Rafts are intended to support densely spaced mussel ropes hung from the framework. When submerged, the pontoons are flooded, and the raft is held vertically by floats attached by lines. The computer models were developed in Aqua-FE？ to simulate the effects of waves and current. They were validated by comparison with wave tank results by use of a 1/10 scale raft physical model. Comparisons showed good agreement for the important heave（vertical） and pitch（rotational） motions, though there was a tendency towards conservative results for wave and current drag. Full-scale simulations of surface and submerged single raft and two rafts connected in tandem were performed. Submerged raft wave response was found to be reduced relative to that at the surface for both the single and two-raft configurations. In particular, the vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. For example, the maximum vertical velocities of mussel rope attachment points in the submerged two raft case were 7%-20% of the corresponding velocities when at the surface.展开更多
基金The National Natural Science Foundation of China under contract Nos 42076058 and 41930538the National Key Research and Development Program of China under contract No.2022YFC3106104the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2023023 and 2019017。
文摘As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.
文摘In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction functions are supposed to be the solving conditions. Next, the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series. Finally, the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.
基金financially supported by the Small Business Innovation Research(SBIR)program of the USDA National Institute for Food and Agriculture(NIFA)(Grant No.2013-33610-21190)to Pemaquid Mussel FarmsDuring her time at the University of New Hampshire where this study was completedsupported by a graduate student fellowship funded by the People’s Republic of China
文摘To investigate the dynamics of submersible mussel rafts, the finite element program Aqua-FETM, developed by the University of New Hampshire（UNH）, was applied to rafts moored at the surface and submerged. The submerged configuration is used to reduce wave forcing and to avoid contact with floating ice during winters in northern waters. Each raft consists of three pontoons connected by a grid framework. Rafts are intended to support densely spaced mussel ropes hung from the framework. When submerged, the pontoons are flooded, and the raft is held vertically by floats attached by lines. The computer models were developed in Aqua-FE？ to simulate the effects of waves and current. They were validated by comparison with wave tank results by use of a 1/10 scale raft physical model. Comparisons showed good agreement for the important heave（vertical） and pitch（rotational） motions, though there was a tendency towards conservative results for wave and current drag. Full-scale simulations of surface and submerged single raft and two rafts connected in tandem were performed. Submerged raft wave response was found to be reduced relative to that at the surface for both the single and two-raft configurations. In particular, the vertical motion of mussel rope connection points was significantly reduced by submergence, resulting in reduced potential for mussel drop-off. For example, the maximum vertical velocities of mussel rope attachment points in the submerged two raft case were 7%-20% of the corresponding velocities when at the surface.
