This is a continuation of SPECMAP, a research program begun in 1979. The general goal of SPECMAP is to advance our understanding of climate dynamics on orbital time scales (10,000 to 100,000 years). Over this frequency band, major changes in the global climate system are externally forced by modulations in the annual cycle of incoming radiation. This phase of SPECMAP research includes a major shift toward an experimental program in which the existing SPECMAP database augmented by crucial new observations, is assimilated into a series of numerical experiments. These experiments will be conducted around three themes: the tropical ocean, high- latitude processes, and the ocean carbon system. This research is important because it provides a rare opportunity (one for which the forcing is known with great precision) to conduct quantitative investigations of the mechanisms of climate change. The specific goal is to understand the physical and chemical mechanisms by which the ocean, coupled to the atmosphere and cryosphere, mediates the climatic response of the earth to orbital forcing by altering the fluxes of heat, salt, and carbon.
