【摘要】 长江来水来沙具有水量沙量大,有明显的季节变化。水量与沙量时而相应时而不相应、流量最大月后的沙量比流量最大月前大等特点.口门附近的悬沙浓度和净输沙量在时间上有明显的涨落潮、大小潮和洪枯季变化。在空间上,三条汉道各异,同一汊道拦门沙内外也有较大差异。北港是目前长江输水输沙的主要通道。流域来沙约有50％以上在南支口门附近沉积,南港口外的水下三角洲是主要淤积区。122°30′E～123°E间是悬沙向东扩散的一条重要界线,入海泥沙主要向东偏南方向扩散。更多还原

【Abstract】 The Changjiang River carries an enormous volume of run-off laden with sediments every year which significantly affects the hydrologic regime, the suspended sediment distribution, the depositional areas, and the ecology of both the Changjiang Estuary and the adjacent sea area.This article is based on data obtained during the three cruises carried out pursuant to the "China-US Joint Study Program of Marine Sedimentation Processes". In it, we discuss the seasonal distribution of the fresh water and sediment discharged from the Changjiang River and their causes, the characteristics of the suspended sediment distribution in the Changjiang Estuary, and the distribution and dispersion of the sediment emptying into the sea. The main characteristics of the fresh water and sediment discharges of the Changjiang River are as follows. The volumes of runoff and sediment discharged are great. There are variations, however, between high runoff and dry seasons. In 60% of the years,the water volume corresponds to the sediment volume. For equal river discharges, the sediment discharge is greater after the month of maximum water discharge month than before the maximum flow discharge month.. Suspended sediment concentrations and net sediment volumes transported to the sea vary with the phase of the tide, namely, between flood and ebb tide, between higher high water and lower high water, between spring and neap tide, and also seasonally and spatially between high runoff and dry seasons. Suspended sediment concentrations differ in the North Channel, the North Passage, and the South Passage, the North Channel being the main outlet to the sea for water and sediment from the river. Even in the same branch, significant differences exist between positions inside and outside the sandbars.More than 50% of sediments from the Changjiang River basin are deposited at the mouth, forming a wide subaqueous delta and sand bar system. The main deposition zone in the past 20 years was the subaqueous delta area outside the South Passage and the North Branch mouths. The region between 122°30’-123°E is an important boundary region, beyond which little suspended sediment disperses. This line basically coincides with the front edge of the subaqueous delta. The suspended sediments debouched by the Changjiang disperse mainly in an east by south direction.更多还原