中文摘要：

在底部边界层(BBL ) 以内的沉积的暂停和免职是在架海控制推迟的沉积的命运的主要动态进程。沉积运输模式的数字学习依靠描述沉积侵蚀和免职的一些批评参数的知识。一批评砍应力在泥区域西南的边基于领域观察被估计离开 Jeju 岛，华东海。根据在借助于声学的仪器的 BBL 以内的速度和推迟的沉积集中的同时的观察包括声学的 Doppler 速度计和一个声学的 Doppler 当前的剖析程序，安定速度被 SSC 的狂暴的摆动在惯性驱散的平衡的假设下面估计。这个方法给 0.20 mm/s 的 0.91 mm/s 和标准差的吝啬的值，它比 Soulsby 的一个实验方法并且由获得的值大一个数量级一在里面 situ 能沉入水中的粒子尺寸分析器。差别是可能由于二方法论的不同性质，惯性驱散的方法 BBL 动力学是更指示的并且因此在安定速度的 situ 估计被相信提供合理，而 Soulsbys 方法对通常合适仍然流水。为基于 SSC 的时间的可变性的统计分析估计侵蚀和免职的批评压力的一个新奇方法(它关于时间被定义为平均深度的 SSC 的衍生物) 并且相应底部砍应力被建议。分别地，侵蚀和免职的两个批评压力与 0.20 Pa 和 0.16 Pa 的相应中部的价值在 0.11 Pa 和 0.25 Pa 之间改变哪个证实侵蚀的批评压力比免职的批评压力有点高。估计的另一个方法批评砍借助于安定速度的应力也被采用，它让步合理批评砍 0.06-0.17 Pa 的压力价值。

英文摘要：

The resuspension and deposition of sediment within a bottom boundary layer（BBL） is the main dynamic processes that control the fate of the suspended sediment in shelf seas.The numerical study of sediment transport patterns relies on the knowledge of some critical parameters that describe sediment erosion and deposition.A critical shear stress is estimated based on field observations at the edge of a mud area southwest off Jeju Island,the East China Sea.On the basis of the simultaneous observation of velocity and suspended sediment concentrations within the BBL by means of acoustic instruments including an acoustic Doppler velocimeter and an acoustic Doppler current profiler,the settling velocity is estimated by turbulent oscillations of the SSC under the assumption of inertial-dissipation balance.This method gives a mean value of 0.91 mm/s and standard deviation of 0.20 mm/s,which is an order of magnitude larger than the value obtained by an empirical method of Soulsby and by an in situ submersible particle size analyzer.The difference is possibly due to the distinct natures of two methodologies,the inertial-dissipation method is more indicative of the BBL dynamics and is thus believed to provide reasonable in situ estimates of the settling velocity,whereas Soulsby＇s method is usually suitable for still water.A novel method for estimating the critical stresses of erosion and deposition based on statistical analyses of the temporal variability of the SSC（which is defined as a derivative of the depth-averaged SSC with respect to time） and the corresponding bottom shear stress is proposed.Both critical stresses of erosion and deposition vary between 0.11 Pa and 0.25 Pa with corresponding median values of 0.20 Pa and 0.16 Pa,respectively,which confirms that the critical stresses of erosion is somewhat higher than the critical stresses of deposition.Another method of estimating the critical shear stress by means of the settling velocity is also employed,which yields reasonable critical shear stress values of