烟台西部近岸海域冬季悬浮泥沙浓度时空变化及其输运特征

TEMPORAL AND SPATIAL VARIATION OF SUSPENDED SEDIMENT CONCENTRATION IN THE NEARSHORE WATERS OF WESTERN YANTAI AND ITS TRANSPORT CHARACTERISTICS IN WINTER

基于2017年12月在烟台港近岸海域6个站位大、小潮期的海流和悬沙同步观测资料,分析了悬浮泥沙浓度的时空变化规律,利用悬浮泥沙通量机制分解方法计算了研究区的悬浮泥沙输运通量,并初步讨论了潮流作用下悬浮泥沙的输运机制。结果表明,研究区各站位悬浮泥沙含量大潮期大于小潮期;大潮期各站位悬浮泥沙浓度多出现2~4个峰值,小潮期各站位悬浮泥沙浓度变化较为复杂,其规律性较弱;悬浮泥沙变化一般滞后于流速变化1~2 h。从平面分布上来看,研究区大潮期各站位悬浮泥沙浓度差异较大,小潮期差异较小;垂向上,大小潮期各层位悬浮泥沙含量变化不大,层化现象较弱。研究区水体的平流输运项主导着这一区域的悬浮泥沙输运,垂向净环流项起辅助作用,其他输沙项的贡献很小,研究区悬浮泥沙净输运方向与余流方向大致一致。大潮期垂向净环流项对悬浮泥沙输运的贡献略大于小潮期,小潮期平流输运项对悬浮泥沙输运的贡献略大于大潮期,大小潮变化对研究区泥沙输运影响显著。

Based on the simultaneous observation of currents and suspended matters in spring and neap tides at six stations in the coastal waters of Yantai Port in December 2017,this paper studied the temporal and spatial variation in suspended sediment concentrations.The transport flux of suspended matter was calculated,and the transport mechanism of suspended sediment under tidal currents discussed.The results show that the suspended sediment content in the spring tide is greater than that in the neap tide;and the concentration of suspended matter at each station has 2~4 peaks during the spring tide period,whereas that in the neap tide is more complicated and lack of regularity.The change in suspended sediment generally lags behind the flow rate change for 1~2 hours.From the view of plane distribution,the concentration of suspended sediment at different stations in the study period is quite different,and the difference in neap tide period is rather small.In the vertical direction,however,the suspended sediment content in each layer of the spring and neap tides has little change,and the stratification phenomenon is not obvious.The advection transport of the water in the study area dominates the suspended sediment transport,while the vertical net circulation plays a supporting role,and the contribution of other sediment transport modes is rather small.The net transport direction and residual flow of suspended sediment in the study area are roughly the same.The contribution of the vertical net circulation to the suspended sediment transport during the spring tide period is slightly larger than that during the neap tide period.The contribution of the advection transport in the neap tidal period to the suspended sediment transport is slightly greater than that during the spring tide period,and the influence of the fluctuation of spring and neap tides on the sediment transport is significant in the area.