风、潮对河流羽流发展影响的模型研究

Model Study of the Influence of Wind and Tide on the Evolution of River Plumes

采用三维斜压海流模型模拟了潮汐混合、离岸风以及上升流风对河流羽流发展的影响.尽管潮汐混合和风的搅动作用均能削弱河流冲淡水浮力引起的垂直层化现象,但是其控制机制有所不同:潮汐混合是通过湍流动能自下向上的耗散来完成的,风搅动的方向恰好相反.通过检验河流羽流在潮汐和渤海夏季多年平均风场共同作用下的发展特征,发现计算得到的表层海水盐度分布与实测值相当吻合,因此可以认为河流羽流发展对于渤海夏季盐度分布起着重要作用.

A 3-D baroclinic ocean model is used to examine the influence of tide, offshore wind and upwellingfavorable wind on the river plume development. Both tidal mixing and wind stirring can weaken the vertical stratification induced by freshwater buoyancy, but different mechanisms dominate such a process： tidal mixing is accomplished through the upward dissipation of turbulent kinetic energy whereas wind stirring is in the opposite direction. By simulating river plume evolution under the combined action of tide and estival wind field averaged over many years, we have found that the modeled salinity distribution is consistent with the observed one rather well, which means the fiver plume development plays an important role in adjusting the salinity distribution in the surface layer of Bohai Sea.