Evaluating and Improving Regional Climate Projections


1. To provide an overview of regional climate downscaling methods, their application and evaluation;
2. To improve communication between the impacts, adaptation, and other user communities and the regional climate downscaling community;
3. To discuss the establishment of an international activity, under the auspices of the WCRP, to help evaluate and improve regional downscaling methods, to foster collaboration on a more coordinated framework to improve the next generation regional climate change projections, and to promote standards in dissemination and use of regional downscaling results.

There is an increasing need for detailed, high-resolution regional information regarding future climate. Such information is needed by scientists in disciplines that require climate information (e.g. hydrologists), decision- and policy-makers, and by those assessing climate change impacts, adaptation and vulnerability. Although climate change projections must necessarily be undertaken with global models, such models will never have sufficient spatial detail for all applications. Constraints on available computing resources will always limit model resolution; therefore, various techniques have been developed for ‘downscaling’ global climate projections (and shorter-term climate predictions) and for producing fine-scale regional climate information. These include nested regional climate models, variable resolution global models, global uniform high-resolution time-slice simulations, statistical downscaling, and/or combinations of these methods.

At present, there is a need for more information in order that users are better able to evaluate the adequacy or applicability of these various methods for a particular problem. The need has also been expressed for a strong coordinated program aimed at evaluating and improving downscaling methods as well as improving the production of the next generation regional climate change projections. Experience in the global climate modelling community has shown the immense value of internationally coordinated model experiments, and the value of the resulting multi-model ensemble in producing credible climate change information and associated measures of uncertainty. Ensemble results from global coupled models have been used extensively in the IPCC assessment reports, but similar ensemble results from regional models or other downscaling methods have not been widely available for most regions of the world. This has limited the use of downscaling products in climate change impact assessment and adaptation studies.

The first objective of this workshop is to summarize what is already known about the attributes of various downscaling methods. The second objective is to discuss the extent to which these methods address the needs of a broad and very inhomogeneous user community. The third objective is to begin discussion of a coordinated international activity, under the World Climate Research Programme (WCRP), that would develop a framework with the following twofold purpose:
i) provide a framework for the evaluation and intercomparison of regional downscaling models and methods as well as defining standards for the preparation and dissemination of model data (perhaps modelled along the lines of the successful series of Coupled Model Intercomparison Projects, and
ii) provide a framework for the production of a multi-model ensemble of regional climate downscaling simulations for regions worldwide, which would significantly enhance the contribution of regional dynamical and statistical downscaling tools to future IPCC assessments.

This workshop will be by invitation, with a combination of invited talks and poster presentations.