As earth system models (ESMs) become increasingly complex, there is a growing need for comprehensive and multifaceted evaluation, analysis, and diagnosis of model results. The relevance of model predictions to the U.S. Department of Energy’s (DOE’s) mission hinges in part on the assessment of quantitative error bounds and levels of uncertainty, requiring repeatable, automated analysis methods and new observational and experimental data to constrain model results.

This scientific focus area (SFA) has pioneered the development and application of new hypothesis-driven diagnostic approaches for evaluating ESM representations of biogeochemical and hydrological processes at site, regional, and global scales; released two open source model benchmarking software packages; and provided international leadership for global biogeochemical and hydrological model benchmarking. The overarching goals of the SFA are to identify and quantify interactions between biogeochemical and hydrological cycles and the earth system, and to quantify and reduce uncertainties in ESMs associated with those interactions.

The SFA will:

1) develop hypothesis-driven approaches for evaluation of ESM biogeochemical and physical process representations at site, regional, and global scales;

2) investigate the degree to which contemporary observations can be used to reduce uncertainties in future scenarios, including use of an “emergent constraint” approach;

3) leverage the growing collection of laboratory, field, and remote sensing data sets for systematic evaluation of ESM biogeochemical processes;

4) conduct intercomparison experiments using DOE’s Energy Exascale Earth System Model (E3SM) framework; and

5) evaluate the performance of biogeochemical and hydrological process representations in ESMs and their interactive effects on the earth system.