南海风生冷暖涡的数值模拟

Numerical Modelings of the Wind Forced Cold and Warm Gyres in the South China Sea

利用美国普林斯顿大学海洋模式（ＰＯＭ）对风应力和海岸线共同作用下的南海冷暖涡生成机制进行了数值模拟。结果表明，风应力的作用总可在其下方的海洋中激发出与风应力旋转方向相同的直接涡旋。当地球自转参数ｆ≠０时，通过埃克曼（ Ｅｋｍａｎ）抽吸作用可在南海分别产生与反气旋性和气旋性海面风应力强迫相对应的暖涡和冷涡。如果ｆ＝０，风应力激发出的直接涡旋流更强，但均为冷性涡旋。β效应使激发出的海洋涡旋东西方向的非对称性增大，并且诱生出一个与直接涡旋反向的间接涡旋，两涡间的海流和海洋西边界流均增强。文中还对上述现象的机理进行了简要讨论。

Numerical simulations of the mechanisms of the formations of the South China Sea cold and warm gyres under the joint effects of the wind stress and the coast lines are made in this paper by use of the Princeton University Ocean Model (POM). The results show that the wind stress can always create a direct gyre below it in the sea with the same direction of rotation. When the earth self-rotation parameter fis not equal to zero, the surface wind stress forcing with anticyclonic or cyclonic vorticity may form a corresponding warm or cold gyre in the South China Sea through the Ekman pumping. If f=0, the forced currents of the direct gyre are stronger and the gyre has a cold core. The β effect increases the asymmetry of the ocean gyre and induces an indirect gyre with the opposite direction of rotation to the direct gyre. The oceanic current between the two gyres and the west boundary current both strengthen. A brief discussion on the mechanism of the above phenomena is given, too. in this paper.