中文摘要：

基于POM（Princeton Ocean Model）海洋模式,对南海不同深度环流的季节性变化进行了数值模拟研究。模拟结果表明：南海表层和上层环流受季风影响,在夏季西南季风驱动下,南海表层环流在南部呈现强反气旋式结构,在南海北部则是一个弱的气旋环流;在冬季东北季风驱动下,南海表层环流结构呈气旋式,并且明显加强了沿越南沿岸向南流动的西边界流;春季和秋季为南海季风的转换期,其对应的环流特征也处于冬季环流与夏季环流的过渡流型,流速与冬季和夏季相比较弱。南海200m层环流的季节变化与表层相似。在500与1 000m层,则出现许多处中尺度漩涡,流场也变得较为紊乱。

英文摘要：

The seasonal variations of the circulations at different depth in the South China Sea are numerically simulated based on the Princeton Ocean Model （POM）.The results show that the surface and the upper circulations in the South China Sea are affected by the monsoon.Driven by the southwest monsoon in summer,the surface circulation in the South China Sea shows a strong anticyclonic structure in the south and becomes a weak cyclonic circulation in the north.When driven by the northeast monsoon in winter,the surface circulation shows a cyclonic structure and strengthens obviously the western boundary current that flows southward along the coast of Vietnam.Spring and autumn are the monsoon switching period in the South China Sea.The circulation characteristics corresponding to this period show a transitional flow pattern between the winter and the summer circulations,with the flow velocity being weaker than those in winter and summer.The seasonal variations of the circulation at 200 m depth in the South China Sea are similar to those of the surface circulation.At the water depth of 500 m and 1 000 m in the South China Sea,many mesoscale whirlpools occur and the flow field there becomes also more disordered.