盐场高度分层下的三维斜压数值模拟

采用基于Backhaus的三维斜压模式计算珠江口水动力特性。改进了原模式的盐度差分格式和方程，采用二阶精度差分格式并引入了物理扩散项。改进后盐度差分方程较好地反映珠江口盐度成层现象。本文给出了两个点的水位数值模拟与实测值的对比，给出了包含8个口门珠江口的计算潮流场及盐场，讨论了盐度高度成层条件下珠江河口水动力特性。     

杭州湾二维盐度扩散问题的一种数值解法

本文给出了杭州湾二维盐度扩散问题的一种数值解法。数学模型选用二维流体动力学方程和扩散方程组成的偏微分方程组,以二维特征偏心差分格式方法计算了两个潮周期的流速与盐度分布,结果与实测值吻合较好,可供研究较大海湾盐度及污染扩散问题时参考。     

斜压海洋动力学的一种三维数值模式──Ⅱ.温度、盐度和垂直涡动粘性系数的计算

根据海水温度和盐度平流扩散方程给出一种数值计算方案并采用混合长度理论给出垂直涡动粘性系数的计算方法。对于温度和盐度方程,其平流过程采用了Lax－Wendroff格式,水平扩散采用显格式,垂直扩散采用隐格式。时间步长主要受平流过程的Courant-Friedrichs-Lewy条件限制。垂直涡动粘性系数计算依据Prandtl混合长度理论,并考虑了海水层化的抑制作用,因而其数值与流场及密度场结构有关。温度、盐度及垂直涡动粘性系数的计算与动力方程中内模态的计算同步进行。应用本模式模拟渤、黄、东海由潮流、密度流和风海流迭加而成的综合海流,得出了良好的结果。     

斜压海洋动力学的一种三维数值模式：Ⅱ.温度,盐度和垂直涡动粘性系数的计？

根据海水温度和盐度平流扩散方程给出一种数值计算方案并采用混合长度理论给出生趣涡动粘性系数的计算方法。对于温度和盐度方程其平流过程采用了Ｌａｘ－Ｗｅｎｄｒｏｆｆ格式,水平扩散彩 显著 式,生趣扩散采用隐格式。     

黄海,渤海底层盐度预报方法的研究

根据二维流体动力学方程和深度平均盐度扩散方程在河口径流量以及蒸发和降水之差为已知情况下构成的闭合方程组，预报出深度平均盐度，然后利用底层盐度与度平均盐度、水深和时间之间的经验关系，给出底层盐度的二维预报。     

两种盐度参数化方案在海冰模式中的应用比较

本文详细介绍了SIS海冰模式中引进两种盐度参数化方案即等盐度方案和盐度廓线方案对海冰模拟所存在的差异。利用盐度廓线方案导出的表征盐度与海冰温度间关系的方程比等盐度方案多出一项,将定义为盐度差异项。盐度差异项对海冰厚度的热力作用表现为：在海冰厚度增长季节（11月到次年5月）,盐度差异项通过升高海冰内部温度,抑制海冰增长;在消融的第一阶段（6．8月）,盐度差异项通过升高海冰内部温度加快海冰消融;在消融的第二阶段（9．10月）,盐度差异项通过降低海冰内部的温度抑制海冰消融。但尺度分析表明,盐度差异项要比方程中队海冰温度作用最大项小1．2个量级,如果采用一级近似,可以略去盐度差异项,因此盐度差异项对海冰增长和消融影响很小。同时利用冰洋耦合模式（ModularOceanModel,MOM4）,分别采用两种盐度参数化方案模拟北极海冰厚度和海冰密集度的季节性变化,模拟结果也表明两种方案模拟得到的海冰厚度和海冰密集度的季节性变化相差甚小。     

黄海、渤海盐度准三维数值预报模式

黄海、渤海盐度的垂直结构具有典型的自模性，而其水平分布又受平流、水平扩散效应及径流等因素的影响。本文根据黄海、渤海实测资料拟合了盐度垂直剖面的自模函数，并结合描述表、底层盐度及上均匀层厚度这３个特征量水平分布的方程，给出盐度三维结构的准三维模式。在模式中，综合考虑了海面风和热输入的强迫作用以及流场的平流、侧向混合及底层混合的影响因素，同时还考虑了径流、蒸发及降水的作用，较客观地反映了盐度的三维分布及其变化的物理过程。试报结果分析表明，模式的功能较好，结果令人满意。     

斜压海洋动力学的一种三维数值模式 Ⅰ.动力学方程数值格式

依据自由海面海洋动力学原始方程建立了一种三维有限差分数值模式,可用于潮波、风暴潮和海流的数值模拟和预报。运动方程和连续方程的数值格式采用内、外模态分离的技术。外模态采用交替方向隐格式,用于计算海面高度和垂直平均流速,时间步长不受Ｃｏｕｒａｎｔ－Ｆｒｉｄｅｒｉｃｈｓ－Ｌｅｗｙ条件限制;内模态采用半隐格式,用于计算海流的垂直２颁布,其时间步长可大于外模态时间步长。模式的计算程度比一般显式模式可快１０倍     

越洋海啸波传播数学模型的研究

应用内外解匹配的方法和驻相法推导了柱坐标系下地震引起的水面波动方程的解,即推导了地震海啸波生成与传播的理论方程,并对越洋地震海啸理论方程进行了求解。基于Boussinesq方程出发,建立了二维越洋海啸波传播数学模型,并对越洋海啸进行了数值计算,计算方法采用有限差分方法,差分格式采用交替方向隐格式(Alternating Direction Implicit即ADI方法)。利用越洋海啸计算模式对发生在大洋中的地震海啸进行了模拟,将数值模拟结果与地震海啸波理论方程的计算结果进行了比较,两种计算结果吻合较好。     

显式完全平方守恒差分格式在近岸海流数值模拟中的应用

用显式完全平方守恒差分格式及其改进分解算法对南海月平均流和海面起伏进行了数值模拟，与隐式完全平方守恒差分格式相比，计算时间可省３—５倍，具有良好的时间效益，而且，其计算效果不比隐式完全平方守恒差分格式差。因此，显式完全平方守恒差分格式及其改进分解算法具有良好的实用价值。     

STATES OF CHLORINITY, SALINITY, ELECTRICALCONDUCTIVITY AND ALKALINITY OF THEZHUJIANG ESTUARY AND THEIRCORRELATIONS

Chlorinity, salinity, alkalinity and conductivity ratio at 15℃ have been determined for the Zhujiang (Pearl River) Estuary, and tome mathematical expressions of relationships between these chemical factors have been derived. These measurements form a basis of understanding the bydrochemical states of thil estuary.     

长江河口盐度锋

根据1988－1991年河口锋面现场调查、上海市海岸带调查及历次标准断面调查资料对长江盐度场及盐度锋进行了分析，提出了由口门至外海纵向上存在着三级锋面现象：内侧锋面即长江河口锋为长江河口水与长江冲淡水的界面；羽状锋是长江口羽状流水与口外混合水的界面，它是长江口最主要的盐度锋面，也是长江口一个重要的生物地球化学带，对河口沉积过程及水下三角洲发育具有重要的影响。外侧锋面即海洋锋，是长江冲淡水的最外边缘。     

Comparison of copper speciation in the Zhujiang River Estuary between summer and winter:implication for upwelling current

The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution trend of these species of copper were compared in two cruises. It was found that, in summer, the total copper content in the Zhujiang River Estuary increased with salinity, while the content office ion copper decreased with salinity. However, in winter, the contents of total copper and free ion copper both decreased with salinity. So, it could be concluded that, copper content and speciation in the Zhujiang River Estuary were regulated by other factors than runoffdiffusion such as upwelling current. In order to prove the spatial trend of rice ion copper content in the Zhujiang River Estuary, the cultivation of Dunaliella tertiolecta in waters obtained from sampling stations with different salinities was carried out, and the copper uptake by algae cells was measured then. It was found that, the cells＇ uptake of copper increased with rice ion copper, not the content of total copper.     

2000年7-8月台湾海峡南部至珠江口附近海域表层温、盐度分析

根据表层温、盐度的观测结果，结合相关断面的CTD调查资料和同期的卫星遥感海表温度图，分析了2000年7月10日到8月2日台湾海峡南部至珠江口附近海域的一些海洋现象，结果表明：(1)在调查期间，东山至惠来沿岸海域存在明显的低温高盐区，海丰和惠来以南近岸海域的海水也具有相对高盐的性质，说明调查期间在闽南、粤东沿岸普遍存在上升流现象；(2)调查期间在台湾海峡南部至珠江口之间陆架—陆坡区附近的多个断面上观测到了较明显的盐度锋面；(3)珠江口外的盐度锋面的位置随时间而不断变化。     

A three-dimensional hydrodynamic and salinity transport model of estuarine circulation with an application to a macrotidal estuary

A three-dimensional semi-implicit finite volume numerical model has been developed and applied to study tidal circulation and salinity stratification in the region of Oujiang River Estuary, China. The model employs horizontally unstructured grids and boundary-fitted coordinate system in the vertical direction. Governing equations consisting of continuity, momentum, and transport equations are all solved in the integral form of the equations, which provides a better representation of the conservative laws for mass, momentum, and transport in the coastal region with complex geometry and bottom bathymetry. The model performance was firstly quantified with skill assessment statistics on the choice of different parameters and validated with observed tidal elevation, current velocity, direction and salinity data over a spring–neap tidal cycle collected in 2006. Numerical results show that the model with wetting–drying capability successfully simulated the tidal currents and salinity fields with a reasonable accuracy and indicate that the Oujiang River Estuary is a macrotidal estuary with strong tidal mixing. In addition, the model results also show that the Oujiang River Estuary is a well-mixed estuary during spring tide. Then, the numerical simulations were performed to compare the hydrodynamic process and salinity distribution before and after a river training, which was conducted by blocking the south branch of the Oujiang River mouth. The results reveal that with the only north access to the sea, the influence of the blocking project on the flood discharge capacity is limited and the incremental velocity is beneficial to the navigation channel maintenance, although it will cause some scour to the embankment. Furthermore, the redistribution of tidal prism passing in or out the north branch makes a little severe salinity intrusion during high tide or low tide. However, the salinity intrusion is still within acceptable range, although it can cause some adverse effect on water intaking of production and life. The variations of salinity levels in Yueqing Bay situated at the north of the river mouth are not obvious, so the blocking project will not bring damage to local aquiculture. However, significant changes of salinity happen inside or outside of the south branch, so enough attention need to be paid to the changes of environment caused by the salinity variation after the blocking project. Overall, by weighing advantages and disadvantages of the blocking project, it is feasible and the model can be considered as a tool for managing and studying estuarine circulation.     

珠江河口氮和磷循环及溶解氧的数值模拟 Ⅱ.模拟结果

将生态型水质模式应用于珠江口模拟研究,模式结果较好地再现了珠江口丰水期营养物质和溶解氧的水平及垂直分布趋势,说明模式已抓住了珠江河口的动力和生化变化的关键过程.进一步的研究表明,丰水期珠江河口计算区域氮处于富裕状态,磷和光照控制着浮游植物的生长.     

Investigation of saltwater intrusion and salinity stratification in winter of 2007/2008 in the Zhujiang River Estuary in China

Saltwater intrusion is a serious environmental problem in the Zhujiang River Estuary(ZRE),which threatens the water supply of fifteen million people.The hydrological observations as well as meteorological and tidal forcing in the winter of 2007/2008 were analyzed to examine the saltwater intrusion in the ZRE.The observational results suggest that the maximum vertical difference of salinity can reach 10 in the Humen Channel during neap tide,but is very small in the Hengmen Channel.The vertically averaged salinity from time series stations during spring tide is higher than that during neap tide.A three-dimensional finite difference model was developed based on the environmental fluid dynamic code(EFDC) to study the mechanism of saltwater intrusion and salinity stratification in the ZRE.By analyzing the salt transport and the temporal variation of saltwater intrusion,the authors found that the net salt transport due to the estuarine circulation during neap tide was more than that during spring tide.This caused salt to advance more into the estuary during neap tide.However,saltwater intrusion was stronger during spring tide than that during neap tide because the spring-neap variation in salt transport was small relative to the total length of the saltwater intrusion.The physical mechanism causing this saltwater intrusion was investigated by a series of sensitivity experiments,in order to examine saltwater intrusion in response to river discharge and winds.The freshwater source was a dominant influencing factor to the saltwater intrusion and controlled salinity structure,vertical stratification and length of the saltwater intrusion.The prevailing northeast monsoon during winter could increase the saltwater intrusion in the ZRE.Though the southwest wind was unfavorable to saltwater intrusion during spring tide,it could increase stratification and saltwater intrusion during neap tide.     

NOTABLE FEATURES OF THE MIXING IN THE LINGDINGYANG BAY

In order to understand the mixing process of saline and fresh water at the estuary of the Zhujiang River (Lingdingyang Bay), the Zhujiang River Conservancy Commission made several field observations from 1978 to 1979. The resulting data indicate that the mixing process is quite unique and complicated. Here demonstrations are made from different angles so as to show the nature of the process.On the whole, the Zhujiang Estuary can be roughly regarded as a vertical partly-mixed type with a lateral salinity gradient.     

2006年夏季珠江冲淡水驱动的上升流

根据珠江口及其附近海域2006年夏季（7-8月）航次水文调查资料，发现调查期间，除了西南季风驱动下的冲淡水东向扩散外，粤西珠江口外冲淡水主要呈西向扩散趋势，并且西向扩散的冲淡水下存在上升流。已有的模型研究中，西南季风下珠江口外没有出现上升流，说明西南季风不是珠江口外上升流产生的主导因素。观测的温盐分布、潜标流速时间序列与走航ADCP流态表明，上升流产生的原因是:（1）口门外冲淡水南向扩展驱动了垂向重力环流；（2）密度跃层以下东北向沿岸流的底边界层Ekman效应；（3）口门外冲淡水团之间的气旋型中尺度涡旋作用。     

基于三层嵌套网格的珠江口冬季盐度层化的数值模拟

运用三层嵌套网格的ROMS模式较好地模拟了2009年冬季珠江口的主要水动力过程和盐度分布。结果表明,珠江口盐度层化具有明显的潮周期变化特征,涨潮时表底层盐度差较小,层化较弱;落潮时层化较强。利用势能异常变化平衡方程分析影响层化的贡献项,结果表明势能异常的平流项和应变项是影响珠江口势能异常变化的主要因素。