RÉSUMÉ
Source : site du WCRP
Regional climate downscaling (RCD) techniques, including both dynamical and statistical methods, are increasingly being utilized to produce regional climate information for impact and adaptation studies. It is thus critical that the potentials and limitations of RCD-based information, along with the related uncertainties, are well understood by the modeling and user communities. Recognizing this need, the World Climate Research Program (WCRP) recently formed a task Force on Regional Climate Downscaling (TFRCD) whose mandate is to:
- Develop a framework to evaluate and possibly improve RCD techniques for use in downscaling global climate projections.
- Foster an international coordinated effort to produce improved multi-model RCD-based high resolution climate change information over regions worldwide for input to impact/adaptation work and to the IPCC 5th Assessment Report (AR5).
- Promote greater interaction and communication between global climate modelers, the downscaling community and end-users to better support impact/adaptation activities.
As a result of the first activities of the TFRCD, and in consultation with the broader scientific community, a framework was initiated called the COordinated Regional climate Downscaling Experiment (CORDEX) aimed at improving coordination of international efforts in RCD research. The present structure of CORDEX is the result of discussions occurred in two meetings held in Toulouse on February 13-15, 2009, and Lund on May 1-5, 2009, along with subsequent email discussions. The main goals of CORDEX can be summarized as follows:
- Provide a quality-controlled data set of RCD-based information for the recent historical past and 21st century projections, covering the majority of populated land regions on the globe. The RCD information will sample uncertainties in Regional Climate Change associated with (i) varying Global Climate Model (GCM) simulations; (ii) varying greenhouse gas (GHG) concentration scenarios; (iii) natural climate variability; and (iv) different downscaling methods. The CORDEX downscaling activities will be based on the latest set of GCM climate scenarios and predictions produced within the 5th Coupled Model Intercomparison Project (CMIP5).
- Define a common set of Regional Climate Model (RCM) domains for dynamical downscaling and define a standard set of variables, frequency and format for output and archival at a number of CORDEX data centres.
- Coordinate a range of RCM simulations for the defined domains, forced by analyses of observations (currently ERA-Interim) to provide a benchmark framework for model evaluation and assessment. This exercise should include also statistical downscaling (SD) methods.
- Encourage and coordinate the development of Regional Analysis and Evaluation Teams to; (i) Evaluate the ensemble of RCD simulations, (ii) Develop a suitable set of regionally-specific metrics for RCD evaluation, (iii) Collect suitable observational data to evaluate high-resolution RCD simulations and (iv) Design experiments to investigate the added-value of RCDs and target future priorities in RCD research.
- Engage the broad RCD community in its activities and discussions.
- Provide support and information to climate impact assessment and adaptation groups interested in utilizing CORDEX RCD material in their research.
A first data portal has been set up at http://cordex.dmi.dk/. In the future, data will not necessarily be stored in one place only. At this site all revisions to data specifications will be published, it will provide access to data, and it contains information on how to deliver data to the archive.
