近15年来长江口控制站徐六泾悬沙变化特征研究

基于近15年的实测数据，分析给出了长江河口控制站徐六泾悬沙浓度和组成的变化特性。研究表明：徐六泾站多年平均表层（2003～2017年）、中层和底层（2010～2017年）含沙量分别为0.07、0.07和0.13 g/L；表层（2004～2017年）、中层和底层（2009～2017年）的中值粒径分别为7.3、9.4和11.0 μm。研究期间，年平均含沙量呈显著下降趋势，洪季较枯季降幅更明显。其中2015～2017年均洪枯季表层含沙量较2003～2005年均值分别降低了57%和20%；表层含沙量在2008年出现明显降低的拐点，2008年之后的洪枯季表层含沙量较之前分别降低56%和44%。悬沙粒度具有一定的波动变化，但没有显著趋势性变化特征，或与样本数量限制和流域内人类活动有关。

Temporal and Spatial Variation of Suspended Sediment in Xuliujing of Yangtze River Estuary for Last 15 years

This study examines suspended sediment concentrations (SSC) and compositions at Xuliujing in the Yangtze Estuary based on field data from 2003 to 2017 (15 years). Data analysis suggests that the average SSC of surface (2003-2017), middle-layer, and bottom (2010-2017) at Xuliujing was 0.07, 0.07, and 0.13 g/L, respectively. Overtime the SSCs exhibit a statistically significant decrease trend over the 15 years. The decline during the wet season is more severe than the dry season. Compared with the average SSC in 2003-2005, the mean SSCs have decreased by 57% and 20% in the wet and dry seasons, respectively, in 2015-2017. The surface SSCs exhibit a change points in 2008, with a mean decrease by 56% and 44% in the wet and dry seasons, respectively. Furthermore, the sediment composition exhibits irregular variations that maybe attributed to human activities, but insignificant directional changes over the study period. The D50 is 7.3, 9.4, and 11.0 μm at surface (2004-2017), middle-layer and bottom (2009-2017), respectively.