2003年2、7月在长江口进行了枯、洪季大规模综合水文观测,本文以此次观测资料为基础,采用数理统计、水文学等方法以江阴-南通-徐六泾-南支-南港-南槽(北槽)的格局对长江河口悬沙浓度的时空变化特征进行了分析研究。分析结果表明:(1)徐六泾节点至江阴潮流界河段主要受径流影响,悬沙浓度比较稳定,而在徐六泾以下多级分汉区段,由于各汉道的分流比等因素的不同,悬沙浓度的分布也存在着差异:(2)悬沙浓度受径流、潮流作用影响具有明显的季节变化,潮周期变化;(3)涨、落潮悬沙浓度大小与流速大小密切相关,但存在着一定的滞后性;(4)单宽输沙量在时空上存在着复杂的变化;(5)在长江口南北槽拦门沙最大浑浊带中,泥沙的再悬浮过程比其他河段复杂多变,同时也存在着一定的规律性、周期性。
Large-scale hydrological observations in the Changiiang Estuary have been respectively carried out in February and July, 2003. Based on these data, characteristics of temporal and spatial variation of suspended sediment concentration in the Changjiang Estuary are studied in the order of from Jiangyin to Xuliujing, to South Branch, to South Channel, to South or North Passage with the mutli - methods of hydrology and statistics. The results show that ( 1 ) the reach from Jiangyin to Nantong is controlled mainly by the runoff current, in which suspended sediment concentration is stable. Suspended sediment concentrations of downstream Xuliujing are different because of the different runoff distribution; (2) the suspended sediment concentrations show tidal and seasonal changes under actions of the runoff and tidal current etc ; (3) suspended sediment concentration during the tidal cycle is related but lagged to the current velocity; (4) temporal and spatial variation of the suspended sediment fluxes is complicated; (5) the process of sediment resuspension is more complicated in the south passage and north passage than other passages, but there is recurrent and inerratic.