Process-Oriented Evaluation of Earth System Model

A prerequisite to understanding and improving Earth system models (ESMs) is the systematic evaluation of the models with observations in a process-oriented approach. Extensive knowledge and experience has been acquired in a variety of international Model Intercomparison Projects (MIPs) that focus on the evaluation and quantification of processes for individual components of an ESM. In addition, progress has been made in the area of quantitative model evaluation using performance metrics, and in the area of model weighting using information on present-day performance. In this talk, results from the Chemistry-Climate Model Validation (CCMVal) activity will be presented to demonstrate the importance of process-oriented and quantitative global model evaluation. In addition, examples for diagnostics that have been successfully applied to coupled ESMs are discussed, targeting some of the main biases in existing models. The talk stresses the need for a coordinated international effort on this topic and the benefits that could be gained by establishing a diagnostic and metrics code repository that facilitates the complex evaluation of ESMs on the long-term.