【摘要】 在长江口区主航槽中利用悬浮物浓度测定系统（ＡＣＰ１） 第一次获得了近底紊流“猝发”（ｂｕｒｓｔ） 和床面泥沙喷发（ｅｊｅｃｔｉｏｎ） 的连续时间序列可视图像和数据，同时利用高分辨率流速仪以及旁侧声纳、热敏式双频测深仪等手段获得了大量底形沙波的实测图像和数据。这些图像和数据结果表明：长江口南支南港之间粗粉砂至极细砂在涨落潮流的作用下，呈现静止———细颗粒泥沙起、悬扬———粗颗粒喷发运移的同时进行大尺度底形运动—细颗粒起扬、悬扬—静止的输移循环模式，即当Ｕ＜ ５０ｃｍ／ｓ，泥沙在底床上基本不运动；５０ｃｍ／ｓ＜ Ｕ＜ ６５ｃｍ／ｓ，小尺度紊流猝发发生，泥沙开始小尺度起扬，并有幕式猝发现象；６５ｃｍ／ｓ＜ Ｕ＜ １００ｃｍ／ｓ 时，小尺度紊流猝发强度和持续宽度急剧增大，床面细颗粒泥沙开始喷发导致床面开始冲淤，形成中小尺度沙波；１００ｃｍ／ｓ＜ Ｕ＜ １１０ｃｍ／ｓ 时，大尺度紊流形成，床面粗颗粒泥沙开始喷发；到了Ｕ＞ １１０ｃｍ／ｓ 时，宏观紊流规模更大，床面粗颗粒泥沙的喷发强度和持续宽度急剧增大，导致床面形成大尺度沙波运动。由于 Ｕ＞ １１０ｃｍ／ｓ的落潮流速远远大于涨潮流速，且落潮最大流速达１３７ｃｍ／ｓ，落急（ 流速＞ ?更多还原

【Abstract】 Coarse silt and very fine sand are usually considered to be transported in the form of plane bedload and washload, especially in the large river estuaries. But first records of viewed nearbed turbulent burst, bed sediment ejection accompanied by small and large scale bedform movement with a continuous time scale of 14 hours are observed by Acoustics Suspended Concentration Profiler(ACP). The transversal and longitudinal large scale bedform are detected by high resolution Thermal Depth Recorder, Sonar Sidescan and D. GPS. These results show that the coarse silt and very fine sand transport has the behaviors of small and large scale bedform movement accompanied by strong re suspension at a water depth of 10-20m in the Changjiang Estuary.更多还原