Benchmarking ecosystem response models with experimental data from long-term CO2 enrichment experiments

• Richard J. Norby
• Paul J. Hanson
• Yiqi Luo
• Ram Oren
• I. Colin Prentice

Abstract
Ecosystem models have been increasingly incorporated into earth system models to predict climatic and atmospheric dynamics. However, ecosystem models themselves are far from perfect and need continued improvement. We will advance this necessary model improvement using some of the longest and most comprehensive data sets on CO2 impacts on ecosystems from field experiments. Twelve ecosystem process and land surface models, which are being used for predicting terrestrial response to atmospheric and climatic change, will be parameterized with site and weather data from the Duke University and Oak Ridge National Laboratory free-air CO2 enrichment (FACE) experiments. We will evaluate the ability of the models to reproduce the measured processes of the carbon, water, and nitrogen cycles of the experimental forest stands and their responses to elevated atmospheric CO2 concentration. Similarities and differences among the models and their components will provide guidance for improving all of the models. With the experimental data as a benchmark for model performance, the utility of the models for extrapolation to environmental change questions can be demonstrated with increased confidence. This working group will include participants who are most familiar with the experimental data, a data manager to assemble and format the data for model input, representatives from diverse modeling groups, and a neutral observer to synthesize model results. This data-model intercomparison project has the potential to provide better scientific outputs for policy making.