长江口外海域含沙量的变化特征

    VARIATION OF SUSPENDED SEDIMENT CONCENTRETION IN OFFSHORE YANGTZE ESTUARY

    • 摘要: 根据2007-2009年的水文泥沙资料,对长江口外海域的潮流及含沙量的变化特征进行了分析探讨。研究表明:长江口外海域的含沙量在冬季要显著高于夏季;潮流在大潮期均出现逐年递增之趋势,在小潮期则出现先增大后减小的态势,而含沙量在近岸海域的大潮期呈现先减小后增大的特征,在小潮期出现逐年下降的趋势,远岸海域的含沙量则在大潮期和小潮期都为逐年增大之趋势;在大小潮不同的潮汐作用下,整个长江口外海域含沙量出现周期性的变化,大潮含沙量远高于小潮含沙量;含沙量的峰值基本都滞后于流速峰值。

       

      Abstract: Hydrologic and sediment data from 2007 to 2009 were analyzed and discussed on the variation of tide current and suspended sediment concentration in the offshore Yangtze estuary. The results show that the sediment concentration was significantly higher in winter rather than in summer; tide current is increasing year by year in the spring tide period,but in the neap tide period tide current increases in the beginning and decreases later on. In the nearshore region,the sediment concentration increases first and then decreases in spring tide period,and deceases year by year in neap tide period. However,in the offshore region,the sediment concentration always increases year by year in spring and neap tide period. The sediment concentration exhibits obvious periodical changes. It is much higher in spring tide period than that in neap tide period. The peak value of sediment concentration commonly lags behind the peak value of current.

       

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