Abstract
A coupled atmosphere-ocean model is used to investigate some important effects of a steep sloping thermocline in the, central Pacific. It is found that the coupled modes are very sensitive to the steepness of the thermocline in the central Pacific Ocean. The wave reflection and modal decomposition processes play an important role in the initial development of the unstable mode and dramatically affect the fates of the oscillation. A sensitivity test is conducted to test the role of western boundary reflection in this particular model. The insensitivity of the western boundary reflection seems to agree with the results of previous research that showed that coupled unstable modes do not necessarily depend on Rossby wave reflections.