长江口南部水域次级羽状锋

On Secondary Plume in the Southern Waters of the Changjiang River Estuary

1994 年11 月 24—25 日 (枯季)， 在长江口南部水域内， 对 2 个定点、2 个段面 ( 24 个站位) 进行了水流流速、盐度及悬沙浓度观测。而后，分别绘制出：( 1 ) 水流流速、盐度和悬沙浓度沿水深、时间变化过程图；( 2 ) 各层水流流速、流向随时间变化过程图。 结果分析表明： 1 ) 实测水流流速、盐度及悬沙浓度垂向、水平分布具不连续性，表明了次级羽状锋的存在； 2 ) 在枯季，相对于径流、波浪而言， 外海潮流对长江口次级羽状锋的影响占主导作用； 3 ) 次级羽状锋可能使得悬沙在南汇东滩附近大量淤积；4)次级羽状锋在长江口与杭洲湾之间的水沙交换中起着一定作用。

：Tidal current velocity, salinity and suspended sediment concentration have been measured at two monitoring stations and along two transects (1994-11-24～-25) in the southern waters of the Changjiang River estuary. Two types of plots have been obtained: (1) time series of current velocity, salinity and suspended sediment concentration (contour lines); (2) time series of current speed and direction measured at six different depths. Those data suggest that 1) the secondary Changjiang River plume is present; 2) the tidal current appears to be a dominant mechanism for the secondary Changjiang River plume during dry season; 3) the secondary Changjiang River plume could result in the deposition of fine suspended sediments on the Nanhui tidal flat; and 4) the secondary Changjiang River plume also plays an important role in the water and sediment exchange between the Changjiang River estuary and the Hangzhou Bay.