基于一个年龄概念的河口污染物输运数值模拟

根据Deleersnijder定义的一个平均年龄概念,运用耦合了物质输运模式的一个三维水动力-富营养化数值模型(HEM-3D),研究了位于美国北卡罗莱纳州Pamlico河口(PRE)的污染物输运时间在不同淡水流量影响下的分布情况。模型结果表明,在正常期,污染物被输运出PRE需要大约65d的时间。而在枯水期和洪水期,污染物分别需要230d和20d时间被输运出PRE。这表明物质输运过程明显受淡水流量的影响。污染物输运时间的空间变化显著受河口中盐度入侵的影响,咸水入侵在其可以达到的最大区域形成了一个盐度锋面,而这个锋面阻碍了污染物向外的输运。盐度层化对输运时间的垂向分布影响显著,输运时间垂向梯度随着盐度层化的增强而增大。

Numerical study on pollutant transport in estuary based on age concept

Using a mean age concept defined by Deleersnijder,we apply the three-dimensional hydrodynamic and eutrophication model HEM-3D to investigate the pollutant age distribution under different river discharge conditions in the Pamlico river estuary (PRE),North Carolina.The model results reveal that it takes about 65 days for pollutant to be transported out of PRE during normal season,while,it takes 230 days and 20 days for pollutant substances to be transported out of PRE during dry and flood seasons,respectively.The time differences indicate that the transport process is a function of river discharge.The spatial variation of the pollutant transport age is significantly affected by the salinity intrusion in the PRE; the later forms a salinity front at its most upstream location.The front inhibits the outward transport of pollutant.The salinity stratification plays an important role in the vertical distribution of the pollutant transport age.The vertical difference in age is enhanced as the salinity stratification increases.