Systematic Evaluation of Land Surface Models Using the International Land Model Benchmarking (ILAMB) Package` (Invited Presentation)

As Earth system models (ESMs) become increasingly complex, there is a growing need for comprehensive and multi-faceted evaluation of model predictions. To advance understanding of biogeochemical processes and their interactions with hydrology and climate under conditions of increasing atmospheric carbon dioxide, new methods are needed that use observations to constrain model predictions, inform model development, and identify needed measurements and field experiments. Improved process parameterizations are needed to constrain energy and water predictions in land surface models and better representations of biogeochemistry–climate feedbacks and ecosystem processes in ESMs are essential for reducing uncertainties associated with projections of climate change during the remainder of the 21^st century. The International Land Model Benchmarking (ILAMB) project seeks to 1) develop internationally accepted benchmarks for land model performance, 2) promote use of benchmarks for model intercomparison projects, 3) strengthen linkages between experimental, remote sensing, and modeling communities, and 4) support the design and development of an open source benchmarking software system. Leveraging work on past model evaluation studies, we have developed two generations of such benchmarking software packages that assess model fidelity on 24 variables in four categories from about 45 data sets; produce graphical global-, regional-, and site-level diagnostics; and provide a hierarchical scoring system. The ILAMBv2 package, publicly released in May 2016, has become an integral part of model verification workflow for rapid model development and calibration cycles for the U.S. Department of Energy’s Accelerated Climate Modeling for Energy (ACME) model and the Community Earth System Model (CESM). We will present results from model analysis using the ILAMB packages, discuss techniques for routine model evaluation, propose coordinated evaluation of the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6) output, and describe new metrics that integrate across carbon, surface energy, hydrology, and land use disciplines.