The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater top...The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region （1）, the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region （II）, the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region （III）, in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region （IV）, on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the off- shore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual weakening tendency from west to east, which is opposite to the trend of the wave conditions out- side the breaking region. The presence of submerged shoal （Dengzhou Shoal）, deep trough （Dengzhou Channel）, islands and irregu- lar topography influnces the wave climate, beach types, wave-induced current features, littoral sediment transport trends and coast- line evolution patterns in the southern Bohai Strait. Human activities, such as the sand exploitation of Dengzhou Shoal and other coastal engineering projects, also influence the beach morphology and coastline evolution.展开更多
Potential sandy coast erosion and socio-economic impacts under sea level rise scenarios as well as socio-economic pathways were assessed in Liaodong Bay.Results show that sea level is projected to rise by 20-43 cm in ...Potential sandy coast erosion and socio-economic impacts under sea level rise scenarios as well as socio-economic pathways were assessed in Liaodong Bay.Results show that sea level is projected to rise by 20-43 cm in Liaodong Bay by 2100.And dry land loss increases in all sea level rise scenarios,with the maximum loss of 32.1 km2 in 2100 under RCP8.5.Coastal erosion results in forced migration,and the forced migration is higher under SSP3 than other pathways due to its higher population growth rate,reaching the highest of 3.1×10^4 under SSP3/RCP8.5 in 2100.Moreover,the differences of forced migration among all scenarios increas after 2050,and the migration increasing rates tend to decrease under RCP2.6 and RCP4.5.The maximum economic loss due to coastal erosion will reach 8.05 billion yuan under SSP5/RCP8.5 in 2100,in which land loss cost is two order less than migration cost,and the share of total erosion-induced economic loss in local GDP varies from 1.12‰ to 4.76‰ under all scenarios,which is an important indicator to draw local government's attention to take measures such as beach nourishment,especially for tourist beaches.Optimally,it is recommended by cost-benefit analysis to carry out nourishment mainly on beaches with high value,while there is no need for nourishment in areas where erosion impacts are negligible.展开更多
基金supported by the National Natural Science Foundation for the Youth(No.41106039)
文摘The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region （1）, the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region （II）, the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region （III）, in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region （IV）, on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the off- shore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual weakening tendency from west to east, which is opposite to the trend of the wave conditions out- side the breaking region. The presence of submerged shoal （Dengzhou Shoal）, deep trough （Dengzhou Channel）, islands and irregu- lar topography influnces the wave climate, beach types, wave-induced current features, littoral sediment transport trends and coast- line evolution patterns in the southern Bohai Strait. Human activities, such as the sand exploitation of Dengzhou Shoal and other coastal engineering projects, also influence the beach morphology and coastline evolution.
基金supported by the NMDIS Youth Fund Study on the contribution rate of sea level rise to coastal erosion of typical coastal segments(2018).
文摘Potential sandy coast erosion and socio-economic impacts under sea level rise scenarios as well as socio-economic pathways were assessed in Liaodong Bay.Results show that sea level is projected to rise by 20-43 cm in Liaodong Bay by 2100.And dry land loss increases in all sea level rise scenarios,with the maximum loss of 32.1 km2 in 2100 under RCP8.5.Coastal erosion results in forced migration,and the forced migration is higher under SSP3 than other pathways due to its higher population growth rate,reaching the highest of 3.1×10^4 under SSP3/RCP8.5 in 2100.Moreover,the differences of forced migration among all scenarios increas after 2050,and the migration increasing rates tend to decrease under RCP2.6 and RCP4.5.The maximum economic loss due to coastal erosion will reach 8.05 billion yuan under SSP5/RCP8.5 in 2100,in which land loss cost is two order less than migration cost,and the share of total erosion-induced economic loss in local GDP varies from 1.12‰ to 4.76‰ under all scenarios,which is an important indicator to draw local government's attention to take measures such as beach nourishment,especially for tourist beaches.Optimally,it is recommended by cost-benefit analysis to carry out nourishment mainly on beaches with high value,while there is no need for nourishment in areas where erosion impacts are negligible.
