中文摘要：

基于2003年2月长江口大面积水沙同步观测资料的分析结果，长江口枯季水沙特性：a）垂线平均流速特性：时间上大潮〉小潮，落潮〉涨潮；纵向上由徐六泾向口门呈“先减小后增大再减少”的变化；断面上北支〉南支，南港〉北港，南槽最小。大潮徐六泾垂线平均流速为102cm／s，浑浊带水域北港最大，为128cm／s；口门水域南槽口外最大，为100cm／s。小潮徐六泾为78cm／s；浑浊带水域北槽最大，为83cm／s；口门水域北港口外最小，为36cm／s。b）垂线平均含沙量特性：时间上大潮〉小潮，涨潮〉落潮；纵向上由徐六泾向口门呈“先增大后减小”的变化；断面上北支〉南支，大潮北港〉南港，小潮南港〉北港，北槽较高，北港大潮较高，小潮最低。大潮徐六泾垂线平均含沙量为0．09kg／m^3；浑浊带水域北港最高，为1．14kg／m^3；口门水域南槽最高，为0.81kg／m^3。小潮时徐六泾为0．06kg／m^3，浑浊带水域北槽最高，为0.99kg／m^3，口门水域北港最低，为0．09kg／m^3。c）无论大小潮，水沙净通量均为北槽〉北港〉南槽。d）0．4H流速和含沙量能近似表示其对应的垂线平均值。南北槽大、小潮的水动力和含沙量分布均匀，变化较小，北港变化较大。e）流速和含沙量梯度表明，紊动强度大潮〉小潮，落潮〉涨潮，水体垂向混合的强度大潮〉小潮，涨、落潮的水体垂向混合的强度差别较小。

英文摘要：

According to hydrological and sediment observations in the large scale in the Changjiang Estuary, the characteristics of current and sediment in Changjiang Estuary are as follows： a ） Depth averaged current speed characteristics： In view of time, it is spring 〉 neap and ebb 〉 flood. In view of latitude, the segence is ＂decreaseincrease- decrease＂ from Xu Liujing to the mouth. And in view of the cross section, it shows the North Branch 〉 the South Branch, the South Channel 〉 the North Channel, and the South Passage is the lowest one. During the spring, the depth averaged current speed of Xu Liujing is 102 cm/s. The speed of The North Channel is the highest one in TM, that is, 128 cm/s. And at the mouth, the speed of the South Passage is the highest one in TM, that is,100 cm/s. During the neap, the depth averaged current speed of Xu Liujing is 78 cm/s. The speed of the North Passage is the highest one in TM, that is, 83 cm/s. And at the mouth, the speed of the North Channel is the highest one in TM, that is, 36 cm/s. b ） Depth averaged SSC： In view of time, it is spring 〉 neap, flood 〉 ebb. In view of latitude, the sequence is ＂increase- decrease＂ from Xu Liujing to the mouth. And in view of cross section, it shows the North Branch 〉 the South Branch, the North Channel 〉 the South Channel during the spring, whereas the South Channel 〉 the North Channel during the neap, and the North Passage is relative higher, and the North Channel is higher during the spring but it is the lowest during the neap. During the spring, the depth averaged SSC of Xu Liujing is 0.09 kg/m^3. The speed of the North Channel is the highest one in TM, that is, 1.14 kg/m^3. And at the mouth, the speed of the South Passage is the highest one, that is, 0.09 kg/m^3. During the neap, the depth averaged SSC of Xu Liujing is 0.06 kg/m^3. The speed of the North Passage is the highest one in TM, that is, 0.99 kg/m^3. And at the mouth, the speed of The North Channel is the lowest one, that is, 0.09 kg/m^3. c ） Both