长江口浑浊带絮凝体特性  

Study on in-situ flocs size in turbidity maximum of the Changjiang Estuary

作　　者：唐建华[1] 何青[1] 王元叶[1] 刘红[1] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062

出　　处：《泥沙研究》2008年第2期27-33,共7页Journal of Sediment Research

基　　金：国家自然科学基金(No.50379014);国家重点基础研究发展规划项目(No.2002CB412403);教育部创新团队(IRT0427)

摘　　要：2005年1月,在长江口浑浊带所在的南槽水域,利用现场激光粒度仪(LISST-100),在不扰动天然细颗粒泥沙絮凝体的情况下,定点连续测量了涨落潮变化过程中表层水体细颗粒泥沙絮凝体的级配谱;并用OBS-3A和ADP同步测得表层水体的含沙量、盐度和流速。数据分析表明,在长江口浑浊带水域存在明显的粘性细颗粒泥沙絮凝现象,絮凝体的形成和破碎过程非常明显:水流动力条件直接导致絮凝体的破碎,盐水则促进絮凝体的形成;水流流速和盐度的变化分别造成了絮凝体的四分之一日和半日周期的变化,在长江口浑浊带水域盐度对粘性细颗粒泥沙絮凝的影响比水动力条件的影响更大且更快;粘性细颗粒泥沙发生絮凝现象的临界粒径为32.5μm左右。这为长江口浑浊带形成机制及长江口粘性细颗粒泥沙动力沉积过程的研究提供了依据。In January 2005,changes in floc size spectrum of suspended fine sediment were measured using the in-situ instrument LISST-100 in the turbidity maximum（TM） of the Changjiang Estuary.At the same time,the data of salinity,SSC and current velocity were obtained with OBS-3A and ADP respectively.The results indicate that there is obvious flocculation in the TM of the Changjiang Estuary.Current velocity causes large flocs to break up into small flocs,and salinity causes small particles to form larger flocs.Current velocity and salinity cause the quarter-diurnal and semi-diurnal variations of floc diameter respectively.Salinity is more important than current velocity in the process of flocculation.The critical diameter for the flocculation of fine cohesive sediment in the TM of the Changjiang Estuary is about 32.5 microns.This study may provide some bases for the research of the TM formation and the sedimentation process of the Changjiang Estuary.

关 键 词：长江口 浑浊带 絮凝体 LISST-100 泥沙 

分 类 号：TV148[水利工程—水力学及河流动力学]