CESM1 Paleo Users Guide

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The Community Earth System Model (CESM1) is a coupled climate model for simulating the earth's climate system. Composed of four separate models simultaneously simulating the earth's atmosphere, ocean, land surface and sea-ice, and one central coupler component, the CESM allows researchers to conduct fundamental research into the earth's past, present and future climate states. Please see the brief overview of the notable model improvements.

The CESM 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 CESM for studying past climates have been published by the community.   Low-resolution versions of CESM1 have been developed and supported to allow paleoclimate researchers to integrate the model for thousands and even tens of thousands of years.  This document outlines the procedures for setting up paleoclimate simulations with CESM1, released in 2010.  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 CESM1.

Bette Otto-Bliesner and Jeff Kiehl