Rapid evaluation framework for the CMIP7 assessment fast track

As Earth system models (ESMs) grow in complexity and in volumes of output data, there is an increasing need for rapid, comprehensive evaluation of their scientific performance. The upcoming Assessment Fast Track for the Seventh Phase of the Coupled Model Intercomparison Project (CMIP7) will require expeditious response for model analyses designed to inform and drive integrated Earth system assessments. To meet this challenge, the Rapid Evaluation Framework (REF), a community-driven platform for benchmarking and performance assessment of ESMs, was designed and developed. The initial implementation of the REF, constructed to meet the near-term needs of the CMIP7 Assessment Fast Track, builds upon community evaluation and benchmarking tools. The REF runs within a containerized workflow for portability and reproducibility and is aimed at generating and organizing diagnostics covering a variety of model variables. The REF leverages best-available observational datasets to provide assessments of model fidelity across a collection of diagnostics. All diagnostics were identified and finally selected with community involvement and consultation. Operational integration with the Earth System Grid Federation (ESGF) will permit automated execution of the REF for specific diagnostics as soon as model data are published on ESGF by the originating modelling centres. The REF is designed to be portable across a range of current computational platforms to facilitate use by modelling centres for assessing the evolution of model versions or gauging the relative performance of CMIP simulations before being published on ESGF. When integrated into production simulation workflows, results from the REF provide immediate quantitative feedback that allows model developers and scientists to quickly identify model biases and performance issues. After the REF is released to the community, its subsequent development and support will be prioritized by an international consortium of scientists and engineers, enabling a broader impact across Earth science disciplines. For instance, the REF will facilitate improvements to models and reductions in uncertainties for projections since ESMs are the main tool for studying the global Earth system. Production of reproducible diagnostics and community-based assessments are the key features of the REF that help to inform mitigation and adaptation policies.