The CCSM2.0 coupled model, released on May 17, 2002, provides the community with a coupled model framework for carrying out climate simulations.
What is a "coupled model"?
CCSM coupled model is based on a framework which divides the complete climate system into component models connected by a coupler. This design requires four component models -- atmosphere, land, ocean, and sea-ice -- each connected to the coupler, and each exchanging data with the coupler only. From a software engineering point of view, the CCSM is not a particular climate model, but a framework for building and testing various climate models for various applications. In this sense, more than any particular component model, the coupler defines the high-level design of CCSM software.