Under the World Climate Research Programme (WCRP) the Working Group on Coupled Modelling (WGCM) established the Coupled Model Intercomparison Project (CMIP) as a standard experimental protocol for studying the output of coupled atmosphere-ocean general circulation models (AOGCMs). CMIP provides a community-based infrastructure in support of climate model diagnosis, validation, intercomparison, documentation and data access. This framework enables a diverse community of scientists to analyze GCMs in a systematic fashion, a process which serves to facilitate model improvement. Virtually the entire international climate modeling community has participated in this project since its inception in 1995. The Program for Climate Model Diagnosis and Intercomparison (PCMDI) archives much of the CMIP data and provides other support for CMIP.
We are now beginning the process towards the IPCC Fifth Assessment Report and with it the CMIP5 intercomparison activity. The CMIP5 (CMIP Phase 5) experiment design has been finalized with the following suites of experiments:
I Decadal Hindcasts and Predictions simulations,
II "long-term" simulations,
III "atmosphere-only" (prescribed SST) simulations for especially computationally-demanding models.
The new ESGF peer-to-peer (P2P) enterprise system (http://pcmdi9.llnl.gov) is now the official site for CMIP5 model output. The old gateway (http://pcmdi3.llnl.gov) is deprecated and now shut down permanently.