What is CESM ?#
CESM is a coupled Earth system model for simulating Earth’s climate system and connected component systems. The model is composed of separate models that simultaneously simulate the Earth’s atmosphere, ocean, land, river run-off, land-ice, and sea-ice. The model components that are coupled through the Common Infrastructure for Modeling the Earth known as CIME.
Figure: CESM3 Structure 
Model Components#
Each model component has a page on the CESM website containing descriptions and documentation for active or prognostic models.
CESM3 documentation is still under development. In the meantime, explore the component models and CIME for CESM2 from the links below.
For development updates and a summary of changes in model components from CESM2 to CESM3, see this website