Grain-size distribution patterns of suspended sediment in response to hydrodynamics on the Dafeng intertidal flat, Jiangsu, China
Grain-size distribution patterns of suspended sediment in response to hydrodynamics on the Dafeng intertidal flat, Jiangsu, China
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江苏大丰潮间带悬浮泥沙粒径分布规律对水动力的响应
DOI：
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发表时间：
2006
影响因子：
1.4
通讯作者：
Wang Yaping
中科院分区：
文献类型：
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作者：
Chen Shenliang;Li Zhanhai;Gao Shu;Wang Yaping
根据2002年和2003年夏季江苏沿海大丰潮间带的实测资料，研究了与再悬浮、沉降和潮汐过程有关的悬浮泥沙的粒度分布模式。悬浮泥沙以细粉沙和极细粉沙为主，平均粒径为7~13μm。一个潮汐周期内悬浮泥沙的粒度分布具有两种类型：一种是时空变化不明显的稳定型，另一种是变化显著的双峰型。影响泥沙粒度分布的主要因素有再悬浮、沉淀物、汛期输入潮间滩的悬沙和海底沉积物的粒度分布。再悬浮增加了悬浮泥沙的粗颗粒含量，增大了悬浮泥沙的平均粒径，使悬浮泥沙的粒度分布与海底泥沙相似，而沉降过程对悬浮泥沙的影响则相反。再悬浮发生时，水体下部悬浮泥沙的粒径分布对流速有明显的响应。在再悬浮和沉降过程影响较弱的地区，不同时期潮间带滩涂不同部位悬浮泥沙的粒度分布基本一致。这种分布是指背景粒度分布，其在大丰潮间带的平均粒度约为7μm。
Patterns of grain-size distributions of suspended sediment in relation to resuspension, settling, and tidal processes are investigated, based on in situ measurements over the Dafeng intertidal flat, on the Jiangsu coast, in the summer of 2002 and 2003. The suspended sediment here is dominated by fine and very fine silt, with a mean grain-size of 7~13 μm. The patterns of the grain-size distributions of suspended sediment during a tidal cycle are characterized by two types: one stable type representing insignificant spatial and temporal variations; and the other bimodal type with significant variations. The main factors influencing the grain-size distributions include resuspension, settling, suspended sediment imported into intertidal flats during the flood phase, and the grain-size distribution of seabed sediment. Resuspension increases the coarse particle content, enhances the mean grain-size of suspended sediment, and results in grain-size distributions for the suspended sediment similar to those of seabed sediment; the settling process has opposite effects on the suspended sediment. When resuspension occurs, the gain-size distributions of suspended sediment in the lower part of water column respond significantly to the current velocity. Where the influence of resuspension and settling processes is weak, the grain-size distributions of suspended sediment appear to be stable and almost identical for the various parts of intertidal flats during different measurement periods. Such distributions are referred to the background grain-size distribution, for which the mean grain-size over the Dafeng intertidal flat is around 7 μm.