不稳定热带海气相互作用中快波的过滤

Ｐｈｉｌａｎｄｅｒ［１］明确指出在热带海气耦合系统中能够存在不稳定的海气相互作用。Ｐｈｉｌａｎｄｅｒ等［２］的数值计算表明，由于海气相互作用，不稳定扰动可以向东传播。Ｙａｍａｇａｔａ［３］和Ｈｉｒｓｔ［４］从理论上也证明了海气之间存在着正反馈过程。巢纪平和张人禾［５］运用一个流场和压力场的高阶平衡近似，即在热带大气和海洋中只存在向西传播的赤道Ｒｏｓｓｂｙ波时，得出了两种介质中向西传播的赤道Ｒｏｓｓｂｙ波通过海气相互作用过程，可以产生向西传的不稳定波。并且在一定条件下，还可出现一类不属于Ｋｅｌｖｉｎ波的向东传的不稳定波，这些结果对解释ＥＮＳＯ事件的传播过程是值得参考的。

THE FILTERING OUT OF THE FAST WAVES IN THE TROPICAL UNSTABLE AIR-SEA INTERACTION MODEL

In the tropical air-sea coupled system,the high frequency of fast coupled waves is meaningless for the studying of the ENSO events.It can be inferred that this kind of fast waves is caused by the high frequency equatorial Rossby waves in the atmosphere.In order to prove this,the high frequency disturbances in the atmosphere in the tropical air-sea coupled system are filtered out,and only the low frequency disturbances which are influential in the long period process are reserved.The results further show that the equatorial Rossby waves in the ocean play a decisive part in the long-term evolution of the tropical air-sea coupled system,which provides a physical foundation for the designing of a model to study and forcast the ENSO events with much less calculating amounts.