A recent history of GFDL's global coupled climate models

At different times during the past twenty years or so, a handful of global atmosphere-ocean general circulation models (AOGCMs) have been referred to casually as "The GFDL climate model". This casual, non-specific terminology can lead to some confusion, since people may not realize that the term has been applied to different models that have different features and yield different results. This brief discussion is intended to provide some introductory information about these different models, with an emphasis on the current family of workhorse models, the GFDL CM2.x models.

The CM2.x models

In 2004, a new family of GFDL climate models (the CM2.x family) was first used to conduct climate research. The GFDL CM2.x models have become the workhorse model for GFDL's climate research. They are being applied to topics focusing on decadal-to-centennial (deccen) time scale issues (including multi-century control experiments and climate change projections), as well as to seasonal-to-interannual (si) problems, such as El Niño research and experimental forecasts.

The CM2.x models represent a clean break from previous generations of GFDL climate models. All the main coupled model components (the atmosphere, ocean, sea ice and land surface models) were developed from new code sets. To use a genetics analogy, if one views the Fortran source code as being our numerical models' DNA, the CM2.x models share minimal genetic material with previous GFDL models. In other words, the CM2.x models belong to a completely different species than the older GFDL R30 and R15 coupled models. Accordingly, one should not expect results drawn from the newer CM2.x model experiments to be entirely consistent with those drawn from previous GFDL R30 and R15 experimental studies.

Starting in October 2004, results from a series of experiments conducted using the GFDL CM2.0 and GFDL CM2.1 models were disseminated via the Internet. And the amount of CM2.X model output being made available to the public continues to grow. Most of these experiments are driven by forcing agents consistent with those requested by the Intergovernmental Panel on Climate Change (IPCC) for their fourth assessment report (AR4), and are applicable to research projects associated with the U.S. Climate Change Science Program CCSP). CM2.X model output files are freely available to the public from the GFDL Data Portal. A subset of the output is among the IPCC Working Group 1 Data served from The Program for Climate Model Diagnosis and Intercomparison (PCMDI) at the Lawrence Livermore National Laboratory. (Note that access to the data on the PCMDI servers is limited to those approved by the IPCC/WGCM committee.)

More information can be found on the GFDL CM2.x Coupled Climate Models web page

Go to the index of GFDL CM2.0 files that can be downloaded from the GFDL Data Portal

Go to the index of GFDL CM2.1 files that can be downloaded from the GFDL Data Portal

GFDL CM2.X files are freely accessible.

Go to the list of GFDL CM2.X FAQs