长江口北槽浮泥周期性变化初探

Periodical changes of mud fluid in the Northern Channel of Changjiang Estuary in China

根据2000年长江口北槽浮泥的实测资料,分析浮泥厚度和体积等几何尺度随时间的变化,发现长江口北槽浮泥存在日、半月和年际三种周期变化;日周期的变化受潮流动力周期的控制,这是由潮流冲刷浮泥形成的悬沙并再絮凝沉积造成的;半月周期的变化受潮流半月周期变化引起的泥沙供给量的变化控制;年周期的变化主要是由影响细颗粒泥沙絮凝沉积的长江口水温的年度变化所控制,泥沙供给和动力的年周期变化也有一定的影响.

On the basis of measured mud fluid data in the Northern Channel of Changjiang Estuary in China, the periodical changes of mud fluid are discussed. It is thought that the mud fluid changes in three kind of periods in the Northern Channel of Changjiang Estuary. It is pointed out that the tidal period is influenced by the tidal velocity change, at which the flood current erodes the mud fluid and results in the mud fluid scale reducing and the slack current makes fine sediments flocculation and deposition and results in the mud fluid scale increasing. The semi-monthly changes of the mud fluid are controlled by the amount of fine sediments supply. The annual period change of the mud fluid is controlled by the water temperature, which controls the fine sediments flocculation in the Changjiang Estuary. The annual change of sediment supply and the dynamics are also important influencing factors.