珠江口冬季盐度锋面变化的动力机制研究  

A Model Study of the Effects of River Discharges and Interannual Variation of Winds on the Plume Front in Winter in Pearl River Estuary

作　　者：郑舒[1] 蔡树群[2] 

机构地区：[1]国家海洋局南海规划与环境研究院,广东广州510300 [2]中国科学院南海海洋研究所,广东广州510301

出　　处：《人民珠江》2017年第7期1-9,共9页Pearl River

基　　金：海洋公共科技研究基金项目(201205015);国家重点基础研究发展计划(2010CB428704和2013CB956101);国家自然科学基金(41025019)

摘　　要：通过利用ECOMSED模式研究珠江口冬季盐度锋面变化的动力机制。模式由风、潮汐和径流驱动,模式结果与实测数据吻合较好。通过分析动量和盐度输运方程表明,在动量方程中,风应力项、压强梯度力项和速度的时间导数项为主要项;而在盐度输运方程中,盐度的时间导数项、水平平流项和垂直混合项为主要项。余流在表层是向海方向,而底层则向陆方向,且强度较表层弱。通过增加大虎的径流量而保持其他3个站点的径流量不变时,锋面位置变化最为明显。南沙、冯马庙径流量的增大对珠江口盐度锋面的影响比较局部且程度相对较弱,而横门径流量的增大则对盐度锋面几乎没有影响。此外,风速越大或风向越偏北,则盐度等值线越往西侧移,盐度锋面也越向北移,风速与风向对盐度锋面影响的不同之处主要集中在珠江口北部域。A three - dimensional numerical model, Estuarine, Coastal and Ocean Modeling System with Sediments（ ECOMSED）, is em- ployed to study the mechanism of plume front in the Pearl River Estuary （PRE） indetail. The model is forced by winds, tides and river discharges. The results were in reasonable agreement with observational data in the PRE. By analyzing momentum and saltwater trans- port balance equations, it was found that the wind stress term, the pressure gradient term and the local time derivative term of velocity were dominant in the momentumequation, while the local time derivative term, the horizontal advective term and the vertical mixingterm of salinity were dominant in the salinity transport equation. The residual current at surface was seaward and stronger, whilst the bottom layer was mainly landward. Anincrease in the river discharge at Dahu inlet seemed to affect the location of plume front obviously among four river inlets. The effect ofriverdischargeincreasein Nansha or Fengmamiao inlet on the plume front of PREwas more local and wea- ker, whilstthe increase of river discharge at Hengmen inlet had little effect on the plume front. Also, it showed that thestronger or more northward winds were, the more westward plume front moved, and the difference between wind speed and wind direction on plume fro- ntwas concentrated in the northern area of PRE.

关 键 词：河口动力 潮流 风生环流 锋面 数值模式 珠江口 

分 类 号：TV148[水利工程—水力学及河流动力学]