A statistic analysis predicting coastal change of the Yellow River abandoneddelta lobe formed from 1964 to 1976 using Landsat TM imagery was conducted by calculating thecoastal erosion/accumulation rates obtained from...A statistic analysis predicting coastal change of the Yellow River abandoneddelta lobe formed from 1964 to 1976 using Landsat TM imagery was conducted by calculating thecoastal erosion/accumulation rates obtained from four different classic profiles and plotting thechange curves of coastline with time. The studies showed that the regularity of the evolution of thecoastline was very obvious after the delta lobe was abandoned. The coastal evolution can be dividedinto three different phases: erosion phase, transition phase and cyclical change phase. At present,the coast has evolved to the cyclical change phase. The natural coastline change cycle is 4 yearsbetween the dam and is 5 years to the west of the dam. In the cyclical change phase, thequasi-equilibrium line of the coast was located near the coastline of 1996, the current coast mayrecede 1.79 km to reach the natural equilibrium coastline. Therefore, some measures must be taken toprotect the dam or the dam will be destroyed by the force of nature. The curves also revealed themagnitude of erosion/accumulation rates would decrease gradually with time. The results of the studyoffer guidance for coast protection, and proves that the evolution of silty coast actually was acyclical change process too.展开更多
The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculat...The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculation show that in this sea area wave and tidal current action should be considered. Based on the above analysis, an equilibrium beach profile calculation model is developed, in which the wave-current interaction is considered while sediment supply and sediment re-deposition are neglected. The model consists of four parts: (1) calculation of wave parameters, (2) calculation of velocity due to wave-current interaction at different water depth, (3) calculation of friction velocity and shear stress at different water depths, and (4) calculation of the amount of sediment erosion, erosion intensity and variation of beach profile. Calculated results are in good agreement with observed data. Finally, the evolution tendency is discussed and the equilibrium beach profile of this coast is calculated. B展开更多
文摘A statistic analysis predicting coastal change of the Yellow River abandoneddelta lobe formed from 1964 to 1976 using Landsat TM imagery was conducted by calculating thecoastal erosion/accumulation rates obtained from four different classic profiles and plotting thechange curves of coastline with time. The studies showed that the regularity of the evolution of thecoastline was very obvious after the delta lobe was abandoned. The coastal evolution can be dividedinto three different phases: erosion phase, transition phase and cyclical change phase. At present,the coast has evolved to the cyclical change phase. The natural coastline change cycle is 4 yearsbetween the dam and is 5 years to the west of the dam. In the cyclical change phase, thequasi-equilibrium line of the coast was located near the coastline of 1996, the current coast mayrecede 1.79 km to reach the natural equilibrium coastline. Therefore, some measures must be taken toprotect the dam or the dam will be destroyed by the force of nature. The curves also revealed themagnitude of erosion/accumulation rates would decrease gradually with time. The results of the studyoffer guidance for coast protection, and proves that the evolution of silty coast actually was acyclical change process too.
文摘The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculation show that in this sea area wave and tidal current action should be considered. Based on the above analysis, an equilibrium beach profile calculation model is developed, in which the wave-current interaction is considered while sediment supply and sediment re-deposition are neglected. The model consists of four parts: (1) calculation of wave parameters, (2) calculation of velocity due to wave-current interaction at different water depth, (3) calculation of friction velocity and shear stress at different water depths, and (4) calculation of the amount of sediment erosion, erosion intensity and variation of beach profile. Calculated results are in good agreement with observed data. Finally, the evolution tendency is discussed and the equilibrium beach profile of this coast is calculated. B
