海-气耦合系统的非线性不稳定行为与年际气候变率

NONLINEAR INSTABILITY BEHAVIOR OF COUPLED AIR-SEA SYSTEM AND ITS RELATION TO THE INTERANNUAL CLIMATE VARIABILITY

中文关键词:  年际变率  ENSO  季节循环  非线性不稳定  锁相  混沌

英文关键词:Interannual variability  ENSO  Seasonal cycle  Nonlinear instability  Phase-locking  Chaos

中文摘要:

      文中从理论上论述了气候系统的基本态—季节循环的非线性不稳定特征,研究了年际气候变率特别是ENSO与季节循环间非线性相互作用,并通过Oxford海-气耦合模式数值实验具体展示了上述理论分析。理论与数值实验表明,海-气耦合系统可经过年周期态失稳^→新周期产生^→与季节循环锁相^→混沌这一系列分岔过程产生类似ENSO的无规则运动。这一规律为正确认识ENSO的动力机制及客观确定简化海-气耦合模式中的参数提供了理论依据。

英文摘要:

      Based on a general discussion about the nonlinear instability characters of the basic state or the seasonal cycle of the climate system, this paper studies the nonlinear interaction between interannual variability (or rather the ENSO) and the seasonal cycle. Oxford model, a coupled air-sea model, is employed to demonstrate this theoretical analysis. Theoret ical and numerical studies indicate that an ENSO-like irregular oscillation of coupled air-sea system can be produced after a series of bifurcat ions which are associated with the loss of stability of annual cycle, the appearance of a new period, its phase locking with annual cycle and the chaos. This provides the basis for both the understanding of the mechanism of ENSO and the parameter determination of a coupled air-sea model.