Welcome to the GCM Data Archive section of the Data Distribution Centre (DDC) of the Intergovernmental Panel on Climate Change (IPCC). This page is the main entry point for users who want to retrieve either monthly mean data available at DDC or information on the models used.

About DDC GCM data archive

The DDC uses the CERA database which is run by the Model and Data group at the MPIfM. A detailed information on the CERA database is available on the Web. You can look here to get more information.

The data is stored on a tape archive which is associated with the (local) database CERA. A data request will initiate a retrieval mechanism that will take some time to transfer the data from tape to disk, therefore users may have to wait before the requested data is transferred.

Due to a change in the data transfer system we currently provide data only in GRIB format (a machine independent, self-descriptive binary format). If you need data in GZIP (compressed ASCII) format you'll have to convert the GRIB data locally.

Information on both formats and the internal data structure is given   here.

You can select between:

• Results from GCM-Runs for the Fourth Assessment Report (AR4) based on the IPCC-SRES scenarios*
• Results from GCM-Runs for the Third Assessment Report (TAR) based on the IPCC-SRES scenarios
• Results from GCM-Runs based on the IPCC-IS92a (or similar) emission scenarios
• Results from GCM-Runs user in the First Assessment Report (FAR) (subset)

 

*You can get some IPCC AR4 Data of DVD's here

GCM data validation

One of the criteria commonly used in selecting a GCM to be used in constructing regional climate scenarios for impact assessment is the performance of the GCM in simulating the present-day climate in the region. This is evaluated by comparing the model outputs with observed climate in the target region, and also over larger scales, to determine the ability of the model to simulate large scale circulation patterns. Examples of graphical comparisons between GCM outputs and observed climate for the 1961-1990 period for subcontinental world regions can be found here.

Variables requested for the Fifth IPCC-Assesemt Report

The Task Group on Data and Scenario Support for Impact and Climate Analysis (TGICA) on its 14th meeting (26.2 - 28.2 2008 in St. Augustin/ Trinidad and Tobago) has approved a list of (proposed) required variables for the next climate model experiments (Fifth IPCC-Assessment Report).
A summary can be found  here.

Publications

• IPCC TAR
• IPCC SRES

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Additional Information

• Definition of terms
• What is a GCM?
• Constructing change fields
• Stochastic weather generators