The Community Climate System Model (CCSM) and its component models have been invaluable tools for the national and international research communities. These models have been used by researchers worldwide, starting with the first version CSM1, to explore problems of both greenhouse and icehouse past climates. They have been shown to be adaptable for both deep-time paleoclimate applications, when the continental configurations were much different from present, to the more near-term past climates of the glacial-interglacial cycles of the last million years. Over 60 research articles using versions of CCSM for studying past climates have been published by the community. Low-resolution versions of CCSM have been developed and supported to allow paleoclimate researchers to integrate the model for thousands and even tens of thousands of years. This technical note outlines the procedures for setting up paleoclimate simulations with CCSM3, the version of CCSM released in 2004. The science of the paleoclimate simulation still rests on the researcher. Choices will need to be made on the appropriate conditions (i.e., land-ocean configuration, topography and bathymetry, ice sheets, vegetation) for the specific paleoclimate research topic being explored. Additional information on the component models and options that may need to be set can be found in the technical notes of these models. We thank all those who have contributed their time and expertise for maintaining the paleoclimate versions of CCSM.
Bette Otto-Bliesner and Jeff Kiehl