摘要
应用一个线性等值浅水模式，在低频近似下研究了热带大洋西部对风应力响应的动力过程。指出，由于西边界将激发出振幅大的Ｋｅｌｖｉｎ波，以及激发出能形成动力边界层结构的Ｒｏｓｓｂｙ短波，这种结构使来自风应力的能量可在边界附近聚集和维持，并向东传播，表明了热带西太平洋对Ｅｌ Ｎｉｏ（Ｌａ Ｎｉａ）事件的形成和发展较热带东太平洋更为重要，因为后者只激发非色散的 Ｒｏｓｓｂｙ长波。一个重要的观点是：热带西太平洋发展成Ｅｌ Ｎｉｏ的初始暖海温距平是在强烈东风应力作用下形成的，当大气改吹西风时，暖的温度距平只是向东传播及进一步发展而已，而西风恰恰是形成 Ｌａ Ｎｉａ事件的前期动力。另一个结果是当风应力停止作用于海洋后，海洋边界上的经圈流仍随时间呈正比的发展，这一类不稳定性的发现加强了对热带酉太平洋在Ｅｌ Ｎｉｏ（Ｌａ Ｎｉａ）发展中作用的认识。
In the condition of low-frequency approximation, a linear equvalent shallow water model is used to study the dynamical processes of the response of the tropical western Pacific to wind sress. It is indicated that the Kelvin wave with large amplitude will have more important effect on response pro- cesses as well as the perturbation move eastward. The Rossby short wave can form dynamical boundary layer structure that urges the energy from wind stress to accumulate and maintain a near west boundary. This study shows that the tropical western Pacific is more important to occurence and devel- opment of El Ni■o/ La Ni■a. When the wind stress is stoped, the meridional oceanic flow near west boundary still develops with time, this new kind of instability stresses the importance of the tropical west- ern Pacific to the development of El Ni■o / La Ni■a.
出处
《大气科学》
CSCD
北大核心
2002年第2期145-160,共16页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展规划项目G1998040900第一部分
国家自然科学基金资助项目49976001
