Chemistry-Climate Model Validation
Activity for SPARC




SPARC has established the Chemistry-Climate Model Validation Activity (CCMVal) for coupled chemistry-climate models (CCMs). The goal of CCMVal is to improve understanding of Chemistry-Climate Models (CCMs) and their underlying GCMs (General Circulation Models) through process-oriented evaluation, along with discussion and coordinated analysis of science results.

One outcome of this effort is expected to be improvements in how well CCMs represent physical, chemical, and dynamical processes. In addition, this effort will focus on understanding the ability of CCMs to reproduce past trends and variability and providing predictions from ensembles of long model runs. Achieving these goals will involve comparing CCM constituent distributions with (robust) relationships between constituent variables as found in observations. This effort is both a model-model and model-data comparison exercise. Key diagnostics with respect to radiation, dynamics, transport, and stratospheric chemistry and microphysics are defined in the CCMVal Evaluation Table. This approach allows modelers to decide (based on their own priorities and resources) which diagnostics to examine in any particular area. The CCMVal activity helps coordinating and organizing CCM model efforts around the world. In this way, the CCM community can provide the maximum amount of useful scientific information for WMO/UNEP and IPCC assessments.

Achieving these goals requires extensive comparisons and evaluations of a wide range of output from a large number of Chemistry-Climate Models (CCMs).  This model output is being stored in the CCMVal archive at the British Atmospheric Data Centre (BADC) for the convenience and necessity of CCMVal activities conducted by investigators associated with the participating modeling groups. The CCMVal activity and model groups are interested in allowing investigators outside of the CCM community to have access to the model archive for the purposes of scientific research and furthering the goals of the CCMVal activity. Those wishing to use the output from CCMVal model runs are requested to become formal "CCMVal Collaborators" and to follow the Guidelines  for CCMVal Collaborators.

Validation of CCMs is a prerequisite for meaningful prediction, but it is only one aspect. The other aspect is to ensure that model predictions are made under the same conditions. However this is a very challenging and complex issue, because experimental choices (e.g. forcing scenarios, specification of SSTs, experimental strategy) are made by different model groups under various constraints, and it is a challenge to coordinate them. In order to try to achieve as much coordination as possible for the 2006 WMO/UNEP Scientific Assessment of Ozone Depletion, relevant boundary conditions and forcing scenarios were specified for the transient runs of the past and the future.  A minimum suite of output diagnostics has been specified, the choice of which depended on a detailed formulation of the scientific questions by the WMO Steering Committee. In this way, the CCM community can provide the maximum amount of useful scientific information to the 2006 WMO/UNEP Scientific Assessment of Ozone Depletion.

If you want to receive CCMVal announcements, please
subscribe to the CCMVal mailing list by filling out the form at

Steering Committee

CCMVal Evaluation Table Participating Models and Model PIs CCMVal Reference
Simulations and Forcings
Guidelines for CCMVal Collaborators List of CCMVal Contributions Notes, Errata and  Updates on the CCMVal Archive CCMVal-1 and CCMVal-2 Directory Structure at BADC
Please read this before you start working with CCMVal data

Data Requests and Formats
CCMVal  Assessment  in support of WMO 2006 Figures of CCMVal Part1&2 Papers Updated with New Runs SPARC CCMVal Report CCMVal Workshops CCMVal Publications
CCMVal  List of Contacts for Observations   CCMVal  Diagnostic Tool and Code Repository AC&C/SPARC Ozone Database for CMIP5

Last modified:  22 July 2009
CCMVal Steering Committee Only
by Veronika Eyring


Impressum / Imprint - Datenschutzerklärung / Privacy Policy