LYAPUNOV EXPONENTS AND PREDICTABILITY OF THE TROPICAL COUPLED OCEAN-ATMOSPHERE SYSTEM

It has recently been proposed that the broad spectrum of interannual v ariability in the tropics with a peak around four years results from a n interaction between the linear low-frequency oscillatory mode of the coupled system and the nonlinear higher-frequency modes of the system . In this study we determine the Lyapunov exponents of the conceptual model consisting of a nonlinear low-order model coupled to a linear os cillator for various values of the coupling constants.