Lateral mixing effects on the vertical stratification and suspended sediment transport

Abstract

As Simpson et al. (1990) emphasized the importance of the straining process in the stratification and mixing in the estuarine circulation process, various researches have investigated on the relative contribution of each process to the overall potential energy anomaly dynamics. However, many numerical works have modeled only in two-dimensions along-channel or the short distance in three-dimensions as Burchard et al. (2008) did. But, as Geyer and MacCready (2010) pointed out, the lateral process must be important in stratification and mixing in an estuary and three-dimensional modeling must be required in the whole along-channel. This study performed a series of three-dimensional modeling and compared two-dimensional models to compared which significant processes we missed in the two dimensional model. The results from the simulations are numerated in terms of the potential energy anomaly (PEA). Each quantified process of the PEA dynamic equation presents the relationships between the Ф-advection, the depth mean straining, vertical mixing and vertical advection. Such terms are investigated to explain how water level, salinity distribution and across velocity in two-dimensional model are slightly different from three-dimension. Additionally, this work introduced a suspended transport model, which was developed to examine the influences of mixing and stratifying processes in one of the marine processes. Keywords: Lateral flow, PEA, stratification, mixing, suspended sediment