莱州湾西南部海域悬浮泥沙浓度变化规律及输运机制

THE CONCENTRATION CHANGE AND TRANSPORT MECHANISM OF SUSPENDED SEDIMENTS IN SOUTHWESTERN LAIZHOU BAY

根据2015年6月莱州湾西南部海域5个站位大小潮25h海流连续同步观测及悬浮泥沙取样资料,分析了研究区悬浮泥沙浓度的时空变化规律;结合通量机制分解法,研究了悬浮泥沙输运机制,并探讨了悬浮泥沙浓度变化的影响因素。结果表明,莱州湾西南部海域悬浮泥沙浓度整体具有由北向南逐渐减小、由表层向底层逐渐增加的趋势;底层悬浮泥沙浓度在涨、落急时段出现峰值;潮周期内悬浮泥沙输运表现出不对称性,并且平流输运在悬浮泥沙输运中起到主导作用;水动力是影响悬浮泥沙浓度变化的主要因素,悬浮泥沙浓度与流速变化基本呈正相关关系,但浓度峰大多滞后流速峰1~2h。

Observations for 25 hours during a spring and neap tide cycle were carried ut at five sites of the southwestern Laizhou Bay on June 2015,together with suspended sediment sampling.Temporal and spatial changes in suspended sediment concentration were studied.The method of flux mechanism analysis was then adopted to study the transport mechanism of the suspended matter and the influence factors of concentration changes.Results show that the concentration of suspended sediment in the southwestern area of Laizhou Bay has a decreasing tendency from north to south and an increasing trend from surface to bottom.The concentration of suspended matter near the bottom peaked in both the ebb and flood tides,which is several times as high as the normal.The sediment transport during a tide cycle is asymmetry,and the advection transport dominates the suspended matter.Facts suggest that hydrodynamics is the principal factor affecting the change in suspended sediment concentration.The suspended sediment concentration has a positive correlation with flow rate.However,the peak concentration is mostly delayed by 1-2h.