长江口枯水期最大浑浊带形成机制  

Formation mechanisms of turbidity maximum in Changjiang Estuary during the dry season

作　　者：高建华[1] 汪亚平[1] 潘少明[1] 王爱军[1] 杨旸[1] 

机构地区：[1]南京大学海岸与海岛开发教育部重点实验室,江苏南京210093

出　　处：《泥沙研究》2005年第5期66-73,共8页Journal of Sediment Research

基　　金：国家自然科学基金(40106009)资助项目;国家重点基础研究发展规划项目(2002CB412401)

摘　　要：用ADCP获得了长江口最大浑浊带内的高频率和高分辨率流速和悬沙浓度数据,对不同定点站位和走航断面的悬沙浓度、流速和盐度数据进行了分析,同时对不同站位的再悬浮通量以及悬沙输运机制也进行了计算,进而讨论了长江口枯水期最大浑浊带的形成机制。结果表明,枯水期的长江口处于淤积状态,再悬浮通量较小,其数量级介于10-4-10-7kg·m-2s-1之间;平均流输运在整个悬沙输送中占主导地位,斯托克斯漂移效应、垂向环流和潮振荡的垂向切变作用对悬沙输运也有着重要作用;通过分析走航断面的数据确定了枯水期中潮期内最大浑浊带的显著分布区域,“潮泵”作用和河口重力环流作用均在该地区最大浑浊带形成中都发挥着重要作用。The high-frequency and resolution current velocity and suspended sediment concentration data have been collected by using Acoustic Doppler Current Profiler （ADCP） at two anchor stations and a cross-section within the south channel of Changjiang Estuary. The suspended sediment concentration, velocity and salinity are analysized. Resuspension flux and suspended sediment transport mechanism of different stations are also calculated. Furthermore, the forming mechanisms of turbidity maximum in the Changjiang Estuary during dry season are discussed. The results show that, the estuary is in siltation status during dry season, and its resuspension flux is small with 10^-4 - 10^-7 kgm^-2s^-1 . The suspended sediment transport in the estuary is dominated by river flow. The storks drift, vertical circulation, and vertical shear effect due to tidal oscillation also play an important role in the suspended sediment transport. The distribution pattern of turbidity maximum has been located between the period of spring and neap tides during low water season by the analysis of transection measurement. The “tidal pumping” effect, resuspension and gravity circulation play important roles in the formation of turbidity maximum.

关 键 词：ADCP 最大浑浊带 再悬浮 长江口 

分 类 号：P343.5[天文地球—水文科学]