Major differences in beach erosion between two neighboring artificial beaches Xiangluwan Beach(XL beach)and Meiliwan Beach(ML beach)in Zhuhai,China,were studied after Super Typhoon Hato.In this study,a fully nonlinear...Major differences in beach erosion between two neighboring artificial beaches Xiangluwan Beach(XL beach)and Meiliwan Beach(ML beach)in Zhuhai,China,were studied after Super Typhoon Hato.In this study,a fully nonlinear Boussinesq wave model(FUNWAVE)-Total Variation Diminishing(TVD)was used to distinguish the main impact factors,their relative contributions,and the hydrodynamic mechanisms underlying the different beach responses.Results show that compared to the ML beach,the main reason for the relatively weak erosion on Xiangluwan(XL)beach was the smaller beach berm height(accounting for approximately 75.9%of the erosion response).Regarding the beach with a higher berm,the stronger wave-induced undertow flow,along with the higher sediment concentration,led to a higher offshore sediment transport flux,resulting in more severe erosion relative to the beach with a smaller berm height.The second most important reason explaining the weak erosion on XL beach was the absence of seawalls(accounting for approximately 17.9%of the erosion response).Wave reflection induced by the seawall could cause higher suspended sediment concentration,resulting in a toe scouring near the seawall.The offshore submerged breakwater protected XL beach slightly(accounting for approximately 6.1%of the erosion response).Due to the higher water level induced by storm surge,most of the wave energy could penetrate through the submerged breakwater.The effect of the larger berm width of XL beach was negligible.Compared to the beach with a larger berm width,the erosion/deposition regions in the beach with a narrower berm width showed shoreward migration,without significant changes in the erosion/deposition extent.Despite of this,the larger berm width could reduce the wave energy reaching the shoreline.This study of the storm stability of artificial beaches may be applied to beach restoration design.展开更多
The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment sourc...The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.展开更多
Eight representative beach profiles on the eastern coast of the Shandong Peninsula are observed and measured in 2011 and 2012 to determine the coastal processes under the lower tropical wind speed condition and the be...Eight representative beach profiles on the eastern coast of the Shandong Peninsula are observed and measured in 2011 and 2012 to determine the coastal processes under the lower tropical wind speed condition and the beach response to and recovery from the tropical storm Meari in a rare typhoon region. The results show that it is the enhancement and directional change of cross-shore and longshore sediment transports caused by Meari that leads to the beach morphological changes, and most of the sediment transports occur during the pre-Meari landing phase. The erosional scarp formation and the berm or beach face erosion are the main geomorphological responses of the beaches to the storm. The storm characteristics are more important than the beach shapes in the storm response process of the beaches on Shandong Peninsula. The typhoon is a fortuitous strong dynamic event, and the effect on the dissipative beach is more obvious than it is on the reflective beach in the study region. Furthermore, the beach trend is the main factor that controlls the storm effect intensity, and it is also closely related to the recovery of the beach profiles.展开更多
This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences.The paper reviews how the three main research methods,...This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences.The paper reviews how the three main research methods, field investigations, numerical modelling, and physical modelling, have been used to study beach morphodynamics during storm sequences.Available quantitative definitions of storm sequences at different sites are presented and discussed.It is shown that the definition of storm sequences is site-specific and requires knowledge of the storm climate, beach characteristics, and the temporal scale of beach recovery.Subsequently, the paper brings together currently available approaches aimed at describing the effect of storm sequences on beach erosion in a general way.The importance of storm chronology and the effects of an extreme storm within a sequence of storms are highlighted.Following that, the more poorly studied aspect of beach recovery in between storms within a sequence is discussed.Three indicators for defining beach recovery, namely the shoreline location, sediment volumes, and the beach state, are identified and compared.Finally, important research needs, including the need for detailed physical modelling, are identified.展开更多
River training walls have been built at scores of locations along the NSW coast and their impacts on shoreline change are still not fully understood. In this study, the Brunswick River entrance and adjacent beaches ar...River training walls have been built at scores of locations along the NSW coast and their impacts on shoreline change are still not fully understood. In this study, the Brunswick River entrance and adjacent beaches are selected for examination of the impact of the construction of major training walls. Thirteen sets of aerial photographs taken between 1947 and 1994 are used in a GIS approach to accurately determine the shoreline position, beach contours and sand volumes, and their changes in both time and space, and then to assess the contribution of both the structures and natural hydrodynamic conditions to large scale (years-decades and kilometres) beach changes. The impact of the training walls can be divided into four stages: natural conditions prior to their construction (pre 1959), major downdrift erosion and updrift accretion during and following the construction of the walls in 1959~1962 and 1966, diminishing impact of the walls between 1966 and 1987, and finally no apparent impact between 1987~1994. The impact extends horizontally about 8 km updrift and 17 km downdrift, and temporally up to 25 years.展开更多
Studies on the erosion processes and protective measures at the downcoast of the Friendship Port in Mauritania have been successfully conducted by means of 3-D movable-bed model using light model-sand. The headland co...Studies on the erosion processes and protective measures at the downcoast of the Friendship Port in Mauritania have been successfully conducted by means of 3-D movable-bed model using light model-sand. The headland control was accepted for the stability of the beach. This paper mainly deals with the shape, orientation, size and erosion depth of the artificial headland. Various forms of headland projects, such as the normal groin, arch groins bending to upcoast ancj to downcoast, offshore breakwater, and T-shaped dike, have been experimentally investigated. Through a comparison of effects of these works on the beach processes, optimized headlands have been obtained, that is, unsymmetrical T-shaped dike or arch groin bending to the downcoast, which has been practically and successfully applied for the stability of beaches.展开更多
Bathing beaches are usually the first to suffer disasters when tsunamis occur,owing to their proximity to the sea.Several large seismic fault zones are located off the coast of China.The impact of each tsunami scenari...Bathing beaches are usually the first to suffer disasters when tsunamis occur,owing to their proximity to the sea.Several large seismic fault zones are located off the coast of China.The impact of each tsunami scenario on Chinese bathing beaches is different.In this study,numerical models of the worst tsunami scenarios associated with seismic fault zones were considered to assess the tsunami hazard of bathing beaches in China.Numerical results show that tsunami waves from the Pacific Ocean could affect the East China Sea coast through gaps between the Ryukyu Islands.The Zhejiang and Shanghai coasts would be threatened by a tsunami from Ryukyu Trench,and the coasts of Hainan and Guangdong provinces would be threatened by a tsunami from the Manila Trench.The tsunami hazard associated with the Philippine Trench scenario needs particular attention.Owing to China’s offshore topography,the sequential order of tsunami arrival times to coastal provinces in several tsunami scenarios is almost the same.According to the tsunami hazard analysis results,Yalongwan Beach and eight other bathing beaches are at the highest hazard level.A high-resolution numerical calculation model was established to analyze the tsunami physical characteristics for the high-risk bathing beaches.To explore mitigating effects of a tsunami disaster,this study simulated tsunami propagation with the addition of seawalls.The experimental results show that the tsunami prevention seawalls constructed in an appropriate shallow water location have some effect on reducing tsunami hazard.Seawalls separated by a certain distance work even better.The analysis results can provide a scientific reference for subsequent preventive measures such as facility construction and evacuation.展开更多
A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is pr...A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is presented. Results of the application indicate that the model is sensitive to the order of the input wave data, and that the effects of long-term wave series and the effects of the mean annual wave conditions on the model are different. Instead of a single wave condition, the wave series will make the calibration and the verification of the model more practical and the results of the model more reasonable.展开更多
A straightforward conceptual method is proposed to quantitatively assess the seasonal-scale tendency of retreatment or advancement on microtidal beaches by using the backshore/foreshore length ratio. This method is ba...A straightforward conceptual method is proposed to quantitatively assess the seasonal-scale tendency of retreatment or advancement on microtidal beaches by using the backshore/foreshore length ratio. This method is based on measuring the cross-shore profile of a beach when it passes through the “transitional state” that separates the high-from the low-energy season, period during which the morphological characteristics of the beach tend to its equilibrium profile. In order to obtain real measurements of backshore (B) and foreshore (F), the definition of the limits bounding these two important components in subaerial beaches is reviewed and discussed. The approach based on the measurement of the?B/F?length ratio assumes that foreshore and backshore have equivalent lengths in beaches that approximate to their state of morphodynamic equilibrium (B/F?~ 1). A backshore length exceeding the foreshore length is indicative of a state of beach recession, with a?B/F?length ratio > 1. When the foreshore length is greater than the backshore length, the shoreline is advancing or, alternatively, it is developing in a state of morphological confinement,?i.e.?due to the presence of a sea cliff, with a?B/F?< 1. This practical method is then tested against 36 sand and gravel microtidal beach profiles measured along the coasts of Basilicata, in southern Italy. The various “beach states” are summarised into seven classes (I-VII), each identified from specific value intervals of the?B/F?length ratio.展开更多
The aim of this paper is to analyze volleyball practice in the beaches of Copacabana(Rio de Janeiro,Brazil)and Carcavelos and Cascais Bay(Cascais,Portugal)and to review the forms of appropriation of public space based...The aim of this paper is to analyze volleyball practice in the beaches of Copacabana(Rio de Janeiro,Brazil)and Carcavelos and Cascais Bay(Cascais,Portugal)and to review the forms of appropriation of public space based on public policies and rules of the sport in question.Our methodology rests on bibliographic review and ethnographic research to map and distinguish the results in two spatial and cultural contexts that are considerably diverse.Results show that even with greater extension of Copacabana beach in comparison with Cascais,volleyball has a relevant impact in both areas.The installation of the necessary equipment for volleyball practice is also a form of impact in the landscape and establishment of territoriality,which is mainly activated when the game happens.展开更多
In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches p...In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches prove low effectiveness of active methods of coastal protection, mostly causing and provoking intensive degradation of the beaches. Article highlights developing and constructing of free and unbounded beaches as an optimal coastal protection approach. Successful example of this approach was developing of coastal zone in 90s, in Gagra (West Georgia), Black Sea. Positive impact of this kind of artificial beach still survives. In the thesis, it is presented an attempt to scientifically prove extrapolation-traduction on the other similar coasts of the recovery of Gagra Zone beach. Based on morphodynamic analysis and comparison, according to the priorities of major features of reinforced coasts, it turned out that coast of three similar objects (Gagra, Ochamchire and Sokhumi) show homogenous aspects. Scientific expediency of providing extrapolation on other similar objects of etalon objects i.e. Gagra Beach recovered by successful coastal protection experiment. Thereby, for the purposes of creating free-artificial beach, choosing of wrecking zone of Ochamchire is based on coastal protection effectiveness and economical principals, including technical-economical effectiveness.展开更多
Using gamma-ray spectrometry, the activity concentration of naturally occurring radionuclides 226Ra, 212Pb, 214Pb, 232Th, and 40K was determined in sand beaches samples from different areas in Guarapari, Espírito...Using gamma-ray spectrometry, the activity concentration of naturally occurring radionuclides 226Ra, 212Pb, 214Pb, 232Th, and 40K was determined in sand beaches samples from different areas in Guarapari, Espírito Santo state, from Brazil. The absorbed dose rates and annual effective dose were calculated and the results were compared with the internationally accepted values as well as others high background radiation areas (HBRAs). The activity concentration of the 232Th in Areia Preta as well as the absorbed dose rates and annual effective dose were higher than the others regions compared. The results show that Areia Preta in Guarapari has higher background found in beaches in world. This work is part of a research project for the natural background determination of the Brazilian coast.展开更多
A major goal of coastal engineering is to develop models for the reliable prediction of short-and longterm near shore evolution.The most successful coastal models are numerical models,which allow flexibility in the ch...A major goal of coastal engineering is to develop models for the reliable prediction of short-and longterm near shore evolution.The most successful coastal models are numerical models,which allow flexibility in the choice of initial and boundary conditions.In the present study,evolutionary algorithms(EAs)are employed for multi-objective Pareto optimum design of group method data handling(GMDH)-type neural networks that have been used for bed evolution modeling in the surf zone for reflective beaches,based on the irregular wave experiments performed at the Hydraulic Laboratory of Imperial College(London,UK).The input parameters used for such modeling are significant wave height,wave period,wave action duration,reflection coefficient,distance from shoreline and sand size.In this way,EAs with an encoding scheme are presented for evolutionary design of the generalized GMDH-type neural networks,in which the connectivity configurations in such networks are not limited to adjacent layers.Also,multi-objective EAs with a diversity preserving mechanism are used for Pareto optimization of such GMDH-type neural networks.The most important objectives of GMDH-type neural networks that are considered in this study are training error(TE),prediction error(PE),and number of neurons(N).Different pairs of these objective functions are selected for two-objective optimization processes.Therefore,optimal Pareto fronts of such models are obtained in each case,which exhibit the trade-offs between the corresponding pair of the objectives and,thus,provide different non-dominated optimal choices of GMDH-type neural network model for beach profile evolution.The results showed that the present model has been successfully used to optimally prediction of beach profile evolution on beaches with seawalls.展开更多
Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear c...Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong Province.In particular,shoreline rotation caused by a shore-normal coastal structure is emphasized.The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/a.Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal engineering.Prior to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/a.However,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation.Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport processes.These findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.展开更多
The fungal community associated with beach sand and plants located along marine coasts are an under-studied area of research despite its potential relevance to human health. In this study, we isolated and identified t...The fungal community associated with beach sand and plants located along marine coasts are an under-studied area of research despite its potential relevance to human health. In this study, we isolated and identified the cultivable mycobiota associated with sand and plants collected along the coast of Gran Canaria (Spain) using culture-dependent and -independent methods. Clinically relevant species belonging to Cryptococcus spp. and related genera such as Naganishia and Papilotrema were isolated and identified from shoreline plants. Moreover, Candida tropicalis was isolated from beach sand, and Aspergillus fumigatus and Aspergillus terreus strains were associated with both types of samples (i.e., plants and beach sand). We conclude that beach sand and shoreline plants are potential reservoirs of fungi of high clinical interest. We recommend including beach sand and plants from the environment when assessing the quality of marine coastal systems. Our results open a framework for studying the natural marine environment and its role in the epidemiology of infectious diseases in order to more accurately manage public health.展开更多
The study investigates the potential of the serpulid tubeworm Ficopomatus sp.,sourced from Jesolo Lido(Venice,Italy),for CCS(Carbon Capture and Storage).Specimens were processed to extract bioactive compounds using a ...The study investigates the potential of the serpulid tubeworm Ficopomatus sp.,sourced from Jesolo Lido(Venice,Italy),for CCS(Carbon Capture and Storage).Specimens were processed to extract bioactive compounds using a 50%polypropylene glycol-water solvent system.Extracts were analysed and purified using column gel filtration chromatography,with fractions identified by TLC(Thin Layer Chromatography)and further characterized for antioxidant and antibacterial activities.Antioxidant activity was detected via DPPH(2,2-Diphenyl-1-Picrylhydrazyl)spraying on TLC plates,while antibacterial activity was evaluated using the antibiogram paper disk diffusion method.Enzyme activity in the fractions was previously confirmed through a bromothymol blue test followed by spectrophotometric analysis.The primary goal was to explore the CCS potential,using an experimental module involving Arduino Uno embedded microprocessor for the CO2 measurement and to confirm the conversion into insoluble carbonates(storage).The most active fraction,identified as S1,showed significant CCS action,confirmed by microscopic observation of calcareous deposits on treated sponges.These findings suggest that Ficopomatus sp.can be used in CCS research highlighting its potential for biotechnological applications in mitigating climate change.The paper underscores the importance of marine organisms in CCS and offers insights into innovative strategies for environmental conservation and carbon management.展开更多
Youu can enjoy both the mountains and beaches in the state of North Carolina!North Carolina's Outer Banks are a string of islands off the North Carolina coast.Besides enjoying the beaches there,you can climb giant...Youu can enjoy both the mountains and beaches in the state of North Carolina!North Carolina's Outer Banks are a string of islands off the North Carolina coast.Besides enjoying the beaches there,you can climb giant sand dunes.You can also climb to the top of a lighthouse and look out over theocean.展开更多
Los Algodones,a small Mexican town of about 7000 people,has the highest concentration of dentists per square mile in the world and is famously known as Molar City.Hundreds of thousands of Americans visit Los Algodones...Los Algodones,a small Mexican town of about 7000 people,has the highest concentration of dentists per square mile in the world and is famously known as Molar City.Hundreds of thousands of Americans visit Los Algodones every year,but they don't come in search of sandy beaches,they come for veneers,root canals and dental implants.展开更多
This work focuses on the problem of monitoring the coastline, which in Portugal’s case means monitoring 3007 kilometers, including 1793 maritime borders with the Atlantic Ocean to the south and west. The human burden...This work focuses on the problem of monitoring the coastline, which in Portugal’s case means monitoring 3007 kilometers, including 1793 maritime borders with the Atlantic Ocean to the south and west. The human burden on the coast becomes a problem, both because erosion makes the cliffs unstable and because pollution increases, making the fragile dune ecosystem difficult to preserve. It is becoming necessary to increase the control of access to beaches, even if it is not a popular measure for internal and external tourism. The methodology described can also be used to monitor maritime borders. The use of images acquired in the infrared range guarantees active surveillance both day and night, the main objective being to mimic the infrared cameras already installed in some critical areas along the coastline. Using a series of infrared photographs taken at low angles with a modified camera and appropriate filter, a recent deep learning algorithm with the right training can simultaneously detect and count whole people at close range and people almost completely submerged in the water, including partially visible targets, achieving a performance with F1 score of 0.945, with 97% of targets correctly identified. This implementation is possible with ordinary laptop computers and could contribute to more frequent and more extensive coverage in beach/border surveillance, using infrared cameras at regular intervals. It can be partially automated to send alerts to the authorities and/or the nearest lifeguards, thus increasing monitoring without relying on human resources.展开更多
Spanish Sand Situated on the Iberian Peninsula in Southwestern Europe, Spain is richly endowed with pic- turesque natural attractions, allur- ing visitors with its pleasant climate, bright sunshine, green hills and li...Spanish Sand Situated on the Iberian Peninsula in Southwestern Europe, Spain is richly endowed with pic- turesque natural attractions, allur- ing visitors with its pleasant climate, bright sunshine, green hills and limpid waters.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.42006176,42330406,U1706220,41901006)the Basic Research Project of the Science and Technology Innovation Development Program of in Yantai(No.2022JCYJ028)。
文摘Major differences in beach erosion between two neighboring artificial beaches Xiangluwan Beach(XL beach)and Meiliwan Beach(ML beach)in Zhuhai,China,were studied after Super Typhoon Hato.In this study,a fully nonlinear Boussinesq wave model(FUNWAVE)-Total Variation Diminishing(TVD)was used to distinguish the main impact factors,their relative contributions,and the hydrodynamic mechanisms underlying the different beach responses.Results show that compared to the ML beach,the main reason for the relatively weak erosion on Xiangluwan(XL)beach was the smaller beach berm height(accounting for approximately 75.9%of the erosion response).Regarding the beach with a higher berm,the stronger wave-induced undertow flow,along with the higher sediment concentration,led to a higher offshore sediment transport flux,resulting in more severe erosion relative to the beach with a smaller berm height.The second most important reason explaining the weak erosion on XL beach was the absence of seawalls(accounting for approximately 17.9%of the erosion response).Wave reflection induced by the seawall could cause higher suspended sediment concentration,resulting in a toe scouring near the seawall.The offshore submerged breakwater protected XL beach slightly(accounting for approximately 6.1%of the erosion response).Due to the higher water level induced by storm surge,most of the wave energy could penetrate through the submerged breakwater.The effect of the larger berm width of XL beach was negligible.Compared to the beach with a larger berm width,the erosion/deposition regions in the beach with a narrower berm width showed shoreward migration,without significant changes in the erosion/deposition extent.Despite of this,the larger berm width could reduce the wave energy reaching the shoreline.This study of the storm stability of artificial beaches may be applied to beach restoration design.
基金The National Natural Science Foundation of China under contract Nos 41930538,42076211 and 42076058the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2022017 and 2019006the China Postdoctoral Science Foundation under contract No.2019M652248.
文摘The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.
基金The National Natural Science Foundation of China under contract No.41030856the Marine Specific Welfare Project of China under contract No.200905008-4the Project of Taishan Scholar
文摘Eight representative beach profiles on the eastern coast of the Shandong Peninsula are observed and measured in 2011 and 2012 to determine the coastal processes under the lower tropical wind speed condition and the beach response to and recovery from the tropical storm Meari in a rare typhoon region. The results show that it is the enhancement and directional change of cross-shore and longshore sediment transports caused by Meari that leads to the beach morphological changes, and most of the sediment transports occur during the pre-Meari landing phase. The erosional scarp formation and the berm or beach face erosion are the main geomorphological responses of the beaches to the storm. The storm characteristics are more important than the beach shapes in the storm response process of the beaches on Shandong Peninsula. The typhoon is a fortuitous strong dynamic event, and the effect on the dissipative beach is more obvious than it is on the reflective beach in the study region. Furthermore, the beach trend is the main factor that controlls the storm effect intensity, and it is also closely related to the recovery of the beach profiles.
基金supported by the EPSRC FloodMEMORY Project(Grant No.EP/K013513/1)the HYDRALAB~+ Integrated Infrastructure Initiative,RESIST(Contract No.654110)Horizon 2020,European Community
文摘This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences.The paper reviews how the three main research methods, field investigations, numerical modelling, and physical modelling, have been used to study beach morphodynamics during storm sequences.Available quantitative definitions of storm sequences at different sites are presented and discussed.It is shown that the definition of storm sequences is site-specific and requires knowledge of the storm climate, beach characteristics, and the temporal scale of beach recovery.Subsequently, the paper brings together currently available approaches aimed at describing the effect of storm sequences on beach erosion in a general way.The importance of storm chronology and the effects of an extreme storm within a sequence of storms are highlighted.Following that, the more poorly studied aspect of beach recovery in between storms within a sequence is discussed.Three indicators for defining beach recovery, namely the shoreline location, sediment volumes, and the beach state, are identified and compared.Finally, important research needs, including the need for detailed physical modelling, are identified.
文摘River training walls have been built at scores of locations along the NSW coast and their impacts on shoreline change are still not fully understood. In this study, the Brunswick River entrance and adjacent beaches are selected for examination of the impact of the construction of major training walls. Thirteen sets of aerial photographs taken between 1947 and 1994 are used in a GIS approach to accurately determine the shoreline position, beach contours and sand volumes, and their changes in both time and space, and then to assess the contribution of both the structures and natural hydrodynamic conditions to large scale (years-decades and kilometres) beach changes. The impact of the training walls can be divided into four stages: natural conditions prior to their construction (pre 1959), major downdrift erosion and updrift accretion during and following the construction of the walls in 1959~1962 and 1966, diminishing impact of the walls between 1966 and 1987, and finally no apparent impact between 1987~1994. The impact extends horizontally about 8 km updrift and 17 km downdrift, and temporally up to 25 years.
文摘Studies on the erosion processes and protective measures at the downcoast of the Friendship Port in Mauritania have been successfully conducted by means of 3-D movable-bed model using light model-sand. The headland control was accepted for the stability of the beach. This paper mainly deals with the shape, orientation, size and erosion depth of the artificial headland. Various forms of headland projects, such as the normal groin, arch groins bending to upcoast ancj to downcoast, offshore breakwater, and T-shaped dike, have been experimentally investigated. Through a comparison of effects of these works on the beach processes, optimized headlands have been obtained, that is, unsymmetrical T-shaped dike or arch groin bending to the downcoast, which has been practically and successfully applied for the stability of beaches.
基金The China-Indonesia Marine and Climate Center Development under contract No.121152000000210003.
文摘Bathing beaches are usually the first to suffer disasters when tsunamis occur,owing to their proximity to the sea.Several large seismic fault zones are located off the coast of China.The impact of each tsunami scenario on Chinese bathing beaches is different.In this study,numerical models of the worst tsunami scenarios associated with seismic fault zones were considered to assess the tsunami hazard of bathing beaches in China.Numerical results show that tsunami waves from the Pacific Ocean could affect the East China Sea coast through gaps between the Ryukyu Islands.The Zhejiang and Shanghai coasts would be threatened by a tsunami from Ryukyu Trench,and the coasts of Hainan and Guangdong provinces would be threatened by a tsunami from the Manila Trench.The tsunami hazard associated with the Philippine Trench scenario needs particular attention.Owing to China’s offshore topography,the sequential order of tsunami arrival times to coastal provinces in several tsunami scenarios is almost the same.According to the tsunami hazard analysis results,Yalongwan Beach and eight other bathing beaches are at the highest hazard level.A high-resolution numerical calculation model was established to analyze the tsunami physical characteristics for the high-risk bathing beaches.To explore mitigating effects of a tsunami disaster,this study simulated tsunami propagation with the addition of seawalls.The experimental results show that the tsunami prevention seawalls constructed in an appropriate shallow water location have some effect on reducing tsunami hazard.Seawalls separated by a certain distance work even better.The analysis results can provide a scientific reference for subsequent preventive measures such as facility construction and evacuation.
基金This work is financially supported by the National Natural Science Foundation of China
文摘A numerical model of shoreline change of sand beaches based on long-term field wave data is proposed, the explicit and implicit finite difference forms of the model are described, and an application of the model is presented. Results of the application indicate that the model is sensitive to the order of the input wave data, and that the effects of long-term wave series and the effects of the mean annual wave conditions on the model are different. Instead of a single wave condition, the wave series will make the calibration and the verification of the model more practical and the results of the model more reasonable.
文摘A straightforward conceptual method is proposed to quantitatively assess the seasonal-scale tendency of retreatment or advancement on microtidal beaches by using the backshore/foreshore length ratio. This method is based on measuring the cross-shore profile of a beach when it passes through the “transitional state” that separates the high-from the low-energy season, period during which the morphological characteristics of the beach tend to its equilibrium profile. In order to obtain real measurements of backshore (B) and foreshore (F), the definition of the limits bounding these two important components in subaerial beaches is reviewed and discussed. The approach based on the measurement of the?B/F?length ratio assumes that foreshore and backshore have equivalent lengths in beaches that approximate to their state of morphodynamic equilibrium (B/F?~ 1). A backshore length exceeding the foreshore length is indicative of a state of beach recession, with a?B/F?length ratio > 1. When the foreshore length is greater than the backshore length, the shoreline is advancing or, alternatively, it is developing in a state of morphological confinement,?i.e.?due to the presence of a sea cliff, with a?B/F?< 1. This practical method is then tested against 36 sand and gravel microtidal beach profiles measured along the coasts of Basilicata, in southern Italy. The various “beach states” are summarised into seven classes (I-VII), each identified from specific value intervals of the?B/F?length ratio.
文摘The aim of this paper is to analyze volleyball practice in the beaches of Copacabana(Rio de Janeiro,Brazil)and Carcavelos and Cascais Bay(Cascais,Portugal)and to review the forms of appropriation of public space based on public policies and rules of the sport in question.Our methodology rests on bibliographic review and ethnographic research to map and distinguish the results in two spatial and cultural contexts that are considerably diverse.Results show that even with greater extension of Copacabana beach in comparison with Cascais,volleyball has a relevant impact in both areas.The installation of the necessary equipment for volleyball practice is also a form of impact in the landscape and establishment of territoriality,which is mainly activated when the game happens.
文摘In the paper, it is discussed reinforced coastal zones with resort-recreational functions, destructed in terms of anthropogenic pressure of the Black Sea, Georgia. Results of many years’ observations and researches prove low effectiveness of active methods of coastal protection, mostly causing and provoking intensive degradation of the beaches. Article highlights developing and constructing of free and unbounded beaches as an optimal coastal protection approach. Successful example of this approach was developing of coastal zone in 90s, in Gagra (West Georgia), Black Sea. Positive impact of this kind of artificial beach still survives. In the thesis, it is presented an attempt to scientifically prove extrapolation-traduction on the other similar coasts of the recovery of Gagra Zone beach. Based on morphodynamic analysis and comparison, according to the priorities of major features of reinforced coasts, it turned out that coast of three similar objects (Gagra, Ochamchire and Sokhumi) show homogenous aspects. Scientific expediency of providing extrapolation on other similar objects of etalon objects i.e. Gagra Beach recovered by successful coastal protection experiment. Thereby, for the purposes of creating free-artificial beach, choosing of wrecking zone of Ochamchire is based on coastal protection effectiveness and economical principals, including technical-economical effectiveness.
基金grateful to FAPEMIG,CNPq and CAPES for financial assistance.
文摘Using gamma-ray spectrometry, the activity concentration of naturally occurring radionuclides 226Ra, 212Pb, 214Pb, 232Th, and 40K was determined in sand beaches samples from different areas in Guarapari, Espírito Santo state, from Brazil. The absorbed dose rates and annual effective dose were calculated and the results were compared with the internationally accepted values as well as others high background radiation areas (HBRAs). The activity concentration of the 232Th in Areia Preta as well as the absorbed dose rates and annual effective dose were higher than the others regions compared. The results show that Areia Preta in Guarapari has higher background found in beaches in world. This work is part of a research project for the natural background determination of the Brazilian coast.
文摘A major goal of coastal engineering is to develop models for the reliable prediction of short-and longterm near shore evolution.The most successful coastal models are numerical models,which allow flexibility in the choice of initial and boundary conditions.In the present study,evolutionary algorithms(EAs)are employed for multi-objective Pareto optimum design of group method data handling(GMDH)-type neural networks that have been used for bed evolution modeling in the surf zone for reflective beaches,based on the irregular wave experiments performed at the Hydraulic Laboratory of Imperial College(London,UK).The input parameters used for such modeling are significant wave height,wave period,wave action duration,reflection coefficient,distance from shoreline and sand size.In this way,EAs with an encoding scheme are presented for evolutionary design of the generalized GMDH-type neural networks,in which the connectivity configurations in such networks are not limited to adjacent layers.Also,multi-objective EAs with a diversity preserving mechanism are used for Pareto optimization of such GMDH-type neural networks.The most important objectives of GMDH-type neural networks that are considered in this study are training error(TE),prediction error(PE),and number of neurons(N).Different pairs of these objective functions are selected for two-objective optimization processes.Therefore,optimal Pareto fronts of such models are obtained in each case,which exhibit the trade-offs between the corresponding pair of the objectives and,thus,provide different non-dominated optimal choices of GMDH-type neural network model for beach profile evolution.The results showed that the present model has been successfully used to optimally prediction of beach profile evolution on beaches with seawalls.
基金The National Nature Science Foundation of China under contract No.42071007the Nature Science Foundation of Hainan Province under contract Nos 422RC665,421QN0883,and 423RC553。
文摘Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong Province.In particular,shoreline rotation caused by a shore-normal coastal structure is emphasized.The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/a.Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal engineering.Prior to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/a.However,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation.Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport processes.These findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.
文摘The fungal community associated with beach sand and plants located along marine coasts are an under-studied area of research despite its potential relevance to human health. In this study, we isolated and identified the cultivable mycobiota associated with sand and plants collected along the coast of Gran Canaria (Spain) using culture-dependent and -independent methods. Clinically relevant species belonging to Cryptococcus spp. and related genera such as Naganishia and Papilotrema were isolated and identified from shoreline plants. Moreover, Candida tropicalis was isolated from beach sand, and Aspergillus fumigatus and Aspergillus terreus strains were associated with both types of samples (i.e., plants and beach sand). We conclude that beach sand and shoreline plants are potential reservoirs of fungi of high clinical interest. We recommend including beach sand and plants from the environment when assessing the quality of marine coastal systems. Our results open a framework for studying the natural marine environment and its role in the epidemiology of infectious diseases in order to more accurately manage public health.
文摘The study investigates the potential of the serpulid tubeworm Ficopomatus sp.,sourced from Jesolo Lido(Venice,Italy),for CCS(Carbon Capture and Storage).Specimens were processed to extract bioactive compounds using a 50%polypropylene glycol-water solvent system.Extracts were analysed and purified using column gel filtration chromatography,with fractions identified by TLC(Thin Layer Chromatography)and further characterized for antioxidant and antibacterial activities.Antioxidant activity was detected via DPPH(2,2-Diphenyl-1-Picrylhydrazyl)spraying on TLC plates,while antibacterial activity was evaluated using the antibiogram paper disk diffusion method.Enzyme activity in the fractions was previously confirmed through a bromothymol blue test followed by spectrophotometric analysis.The primary goal was to explore the CCS potential,using an experimental module involving Arduino Uno embedded microprocessor for the CO2 measurement and to confirm the conversion into insoluble carbonates(storage).The most active fraction,identified as S1,showed significant CCS action,confirmed by microscopic observation of calcareous deposits on treated sponges.These findings suggest that Ficopomatus sp.can be used in CCS research highlighting its potential for biotechnological applications in mitigating climate change.The paper underscores the importance of marine organisms in CCS and offers insights into innovative strategies for environmental conservation and carbon management.
文摘Youu can enjoy both the mountains and beaches in the state of North Carolina!North Carolina's Outer Banks are a string of islands off the North Carolina coast.Besides enjoying the beaches there,you can climb giant sand dunes.You can also climb to the top of a lighthouse and look out over theocean.
文摘Los Algodones,a small Mexican town of about 7000 people,has the highest concentration of dentists per square mile in the world and is famously known as Molar City.Hundreds of thousands of Americans visit Los Algodones every year,but they don't come in search of sandy beaches,they come for veneers,root canals and dental implants.
文摘This work focuses on the problem of monitoring the coastline, which in Portugal’s case means monitoring 3007 kilometers, including 1793 maritime borders with the Atlantic Ocean to the south and west. The human burden on the coast becomes a problem, both because erosion makes the cliffs unstable and because pollution increases, making the fragile dune ecosystem difficult to preserve. It is becoming necessary to increase the control of access to beaches, even if it is not a popular measure for internal and external tourism. The methodology described can also be used to monitor maritime borders. The use of images acquired in the infrared range guarantees active surveillance both day and night, the main objective being to mimic the infrared cameras already installed in some critical areas along the coastline. Using a series of infrared photographs taken at low angles with a modified camera and appropriate filter, a recent deep learning algorithm with the right training can simultaneously detect and count whole people at close range and people almost completely submerged in the water, including partially visible targets, achieving a performance with F1 score of 0.945, with 97% of targets correctly identified. This implementation is possible with ordinary laptop computers and could contribute to more frequent and more extensive coverage in beach/border surveillance, using infrared cameras at regular intervals. It can be partially automated to send alerts to the authorities and/or the nearest lifeguards, thus increasing monitoring without relying on human resources.
文摘Spanish Sand Situated on the Iberian Peninsula in Southwestern Europe, Spain is richly endowed with pic- turesque natural attractions, allur- ing visitors with its pleasant climate, bright sunshine, green hills and limpid waters.