One of the major problems in understanding the link between Milankovich forcing and the climate of the late Pleistocene lies in the, as yet, unexplained global synchronaeity of glacial-interglacial events. In this study, we isolate a part of the climate system, the coupled ocean-atmosphere tropical Pacific, and test its sensitivity to changes in solar forcing associated with changes in the Earth's orbital parameters.
We use a simplified coupled ocean-atmosphere model which is run for 150,000 years, and forced with Milankovich changes in the solar forcing. This system responds primarily to the precessional cycle in solar forcing, and is capable of generating an annual mean response to the changes in the seasonal distribution of solar radiation where the annual mean insolation is roughly constant. The mechanism responsible for the annual mean response is the interaction between an altered seasonal cycle and the El Nino/Southern Oscillation. The hypothesis is advanced that such changes in the tropical climate can generate a globally synchronous climate response to Milankovich forcing.