摘要
2003年11月在长江口南槽用ADCP进行定点水文观测,结果表明研究区为不规则半日潮,在水流转向期流速较低时常出现悬沙浓度峰值。根据流速对数剖面分布模型与悬沙分布模型,分别计算了海底边界层参数,其中潮周期内摩阻流速可达0.15 m/s,粗糙长度为0.01~1.2 m,拖曳系数为10-3~10-4,边界层厚度为2~4 m,悬沙的沉降速率为0.2~6 mm/s。
Hydrodynamic parameters have been measured using an RDI WH600 ADCP at Nancao,the Yangtze River estuary in November 2003.The acoustic signals recorded have a significant relationship with the suspended sediment concentrations(SSCs) obtained by in-situ water sampling during the measurements.Then the acoustic SSC models have been established to convert ADCP acoustic signals into high-resolution SSCs.The water levels and current velocities show that the study area is characteristic of irregular semi-diurnal tide.In addition,the peak SSC is present at the turn of tidal current,which may have resulted from the velocity shear.On the basis of von Karman-Prandl logarithmic velocity profile and Rose SSC profile,the bottom boundary layer parameters are estimated: the shear velocity can reach up to 0.15 m/s,and the bed roughness length is 0.01~1.2 m.The drag coefficient is 10^(-3)~10^(-4),and bottom boundary layer thickness is 2~4 m.The suspended sediment settling velocity is 0.2~6 mm/s,which is consistent with the results from previous study.
出处
《海洋地质动态》
2006年第7期16-20,共5页
Marine Geology Letters
基金
国家自然科学基金项目(40106009)
国家重点基础研究发展规划项目(2002CB412401)
关键词
海底边界层
流速
悬沙浓度
沉降速度
长江口
bottom boundary layer
current velocity
suspended sediment concentration
suspended sediment settling velocity
the Yangtze River estuary
