Low tide terrace beach is a main beach type along South China coasts with strong tidal actions.How strong tides affect wave transformations on low tide terrace beach still remains unclear.In this study,in-situ measure...Low tide terrace beach is a main beach type along South China coasts with strong tidal actions.How strong tides affect wave transformations on low tide terrace beach still remains unclear.In this study,in-situ measurements are conducted on the low terrace beach at Xisha Bay to provide quantitative descriptions of wave shoaling and shore-breaker phenomena under the tidal effects.It is found that wave breaking is unsaturated on the low tide terrace beach at Xisha Bay.Magnitudes of wave skewness and asymmetry increase as wave shoals and achieve the maximum value at the shore-breaker,and then decrease rapidly.Mean energy dissipation rates of shore-breakers are tide-modulated since the bottom slope changes at the shoreward boundary of wave propagation in a tidal cycle.The remaining wave energy flux at the initialization of the shore-breaker is 1%–12%of offshore wave energy flux,and the energy flux ratio decreases with increasing offshore wave heights.Wave attenuation at shore-breakers can be estimated directly from offshore wave conditions based on findings in this study,favoring designs of seawalls or beach nourishment projects.Field datasets on wave transformations can also be used for verifications of wave numerical models.展开更多
The headland-bay beach is one of the most common coastal types in the world.Its morphology reflects the changes that occurred during long-term evolution of the sandy coast.Several headland-bay beach models have been p...The headland-bay beach is one of the most common coastal types in the world.Its morphology reflects the changes that occurred during long-term evolution of the sandy coast.Several headland-bay beach models have been proposed to simulate the coastline’s configuration in equilibrium.In this paper,a new elliptical model is proposed,described,and applied.On the east coast of Laizhou Bay in Shandong Province from Longkou Port to Diaolongzui,four typical headland-bay beaches have developed,and four headland-bay beach models are used in this paper to simulate the morphology of these beaches to assess the applicability of each model.The simulation results of the elliptical model verify that it is applicable to the study area.In addition,the elliptical model is easy to use.Through simulation and field investigations,we concluded that most of the coastal segments in this area will remain in an erosion state,and the human activity has a significant impact on the shoreline’s evolution.展开更多
Allocosa brasiliensis is a sand-dwelling wolf spider considered a good bioindicator to evaluate the quality of coastal dune ecosystems from Uruguay. Habitat fragmentation and human activities have impacted and reduced...Allocosa brasiliensis is a sand-dwelling wolf spider considered a good bioindicator to evaluate the quality of coastal dune ecosystems from Uruguay. Habitat fragmentation and human activities have impacted and reduced the Southern Uruguayan coast during the last decades. The aim of the present study was to evaluate the density, surface activity and habitat preference of A. brasiliensis in beaches with different human impact. For that purpose, we sampled during the night with head lamps and applied the capture-mark-recapture method. Females were more abundant than males and were the most recaptured sex. The most fragmented beaches showed lower number of burrows and individuals, especially in immatures stages. We found that the most suitable sandy habitat for A. brasiliensis should present a vegetation cover optimum of 25% - 50% of the surface. This study could provide tools for the implementation of future management conservation plans of the Southern Uruguayan coastline.展开更多
High waves and storm surges caused by typhoon(or storm)are the disaster eventsfor the serious erosion in coasts,to which scientists have paid close attention.However,there have been little report on the response proce...High waves and storm surges caused by typhoon(or storm)are the disaster eventsfor the serious erosion in coasts,to which scientists have paid close attention.However,there have been little report on the response processes of the beach morphologiesin different sections of the arc-shaped coast to such calamities.A sequence of beachchanges that were measured in the field during the Typhoon 8616 at the arc-shaped coastof the Shuidong in Guangdong Province,South China is analyzed in this note.展开更多
基金The Key Program of National Natural Science Foundation of China under contract No.41930538the Open Research Fund of State Key Laboratory of Estuarine and Coastal Research,East China Normal University under contract No.SKLEC-KF202203+3 种基金the National Natural Science Foundation of China under contract No.52201317the National Key Research and Development Program under contract No.2022YFC3106102the China Postdoctoral Science Foundation under contract No.2022M711023the Jiangsu Funding Program for Excellent Postdoctoral Talent under contract No.2022ZB148.
文摘Low tide terrace beach is a main beach type along South China coasts with strong tidal actions.How strong tides affect wave transformations on low tide terrace beach still remains unclear.In this study,in-situ measurements are conducted on the low terrace beach at Xisha Bay to provide quantitative descriptions of wave shoaling and shore-breaker phenomena under the tidal effects.It is found that wave breaking is unsaturated on the low tide terrace beach at Xisha Bay.Magnitudes of wave skewness and asymmetry increase as wave shoals and achieve the maximum value at the shore-breaker,and then decrease rapidly.Mean energy dissipation rates of shore-breakers are tide-modulated since the bottom slope changes at the shoreward boundary of wave propagation in a tidal cycle.The remaining wave energy flux at the initialization of the shore-breaker is 1%–12%of offshore wave energy flux,and the energy flux ratio decreases with increasing offshore wave heights.Wave attenuation at shore-breakers can be estimated directly from offshore wave conditions based on findings in this study,favoring designs of seawalls or beach nourishment projects.Field datasets on wave transformations can also be used for verifications of wave numerical models.
基金supported by the Marine Public Benefit Scientific Research Special Fund Project of the State Oceanic Administration (Nos. 200905008 and 201405037)
文摘The headland-bay beach is one of the most common coastal types in the world.Its morphology reflects the changes that occurred during long-term evolution of the sandy coast.Several headland-bay beach models have been proposed to simulate the coastline’s configuration in equilibrium.In this paper,a new elliptical model is proposed,described,and applied.On the east coast of Laizhou Bay in Shandong Province from Longkou Port to Diaolongzui,four typical headland-bay beaches have developed,and four headland-bay beach models are used in this paper to simulate the morphology of these beaches to assess the applicability of each model.The simulation results of the elliptical model verify that it is applicable to the study area.In addition,the elliptical model is easy to use.Through simulation and field investigations,we concluded that most of the coastal segments in this area will remain in an erosion state,and the human activity has a significant impact on the shoreline’s evolution.
文摘Allocosa brasiliensis is a sand-dwelling wolf spider considered a good bioindicator to evaluate the quality of coastal dune ecosystems from Uruguay. Habitat fragmentation and human activities have impacted and reduced the Southern Uruguayan coast during the last decades. The aim of the present study was to evaluate the density, surface activity and habitat preference of A. brasiliensis in beaches with different human impact. For that purpose, we sampled during the night with head lamps and applied the capture-mark-recapture method. Females were more abundant than males and were the most recaptured sex. The most fragmented beaches showed lower number of burrows and individuals, especially in immatures stages. We found that the most suitable sandy habitat for A. brasiliensis should present a vegetation cover optimum of 25% - 50% of the surface. This study could provide tools for the implementation of future management conservation plans of the Southern Uruguayan coastline.
基金Project supported by the National Natural Science Foundation of China.
文摘High waves and storm surges caused by typhoon(or storm)are the disaster eventsfor the serious erosion in coasts,to which scientists have paid close attention.However,there have been little report on the response processes of the beach morphologiesin different sections of the arc-shaped coast to such calamities.A sequence of beachchanges that were measured in the field during the Typhoon 8616 at the arc-shaped coastof the Shuidong in Guangdong Province,South China is analyzed in this note.
