The North American Carbon Program Multi-scale Synthesis and Terrestrial Model Intercomparison Project – Part 2: Environmental driver data

Y. Wei, S. Liu, D.N. Huntzinger, A.M. Michalak, N. Viovy, W.M. Post, C.R. Schwalm, K. Schaefer, A.R. Jacobson, C. Lu, H. Tian, D.M. Ricciuto, R.B. Cook, J. Mao and X. Shi


SUMMARY

Terrestrial biosphere models are often used to represent the land-atmosphere exchange of carbon at regional to global scales, but estimates vary greatly across existing models. These differences stem from specific choices in environmental driver data used to run the models, how the models are spun-up and run, as well as structural differences in how individual models represent biospheric processes. The Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) is designed to isolate the impact of model structural differences, by prescribing a detailed protocol that all participating models follow. This manuscript gives an overview of the environmental driver data compiled for the MsTMIP simulations.

Figure: HWSD topsoil reference bulk density before (top) and after (bottom) correction at 0.5 resolution.

ABSTRACT

Ecosystems are important and dynamic components of the global carbon cycle, and terrestrial biospheric models (TBMs) are crucial tools in further understanding of how terrestrial carbon is stored and exchanged with the atmosphere across a variety of spatial and temporal scales. Improving TBM skills, and quantifying and reducing their estimation uncertainties, pose significant challenges. The Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) is a formal multi-scale and multi-model intercomparison effort set up to tackle these challenges. The MsTMIP protocol prescribes standardized environmental driver data that are shared among model teams to facilitate model–model and model–observation comparisons. This paper describes the global and North American environmental driver data sets prepared for the MsTMIP activity to both support their use in MsTMIP and make these data, along with the processes used in selecting/processing these data, accessible to a broader audience. Based on project needs and lessons learned from past model intercomparison activities, we compiled climate, atmospheric CO2 concentrations, nitrogen deposition, land use and land cover change (LULCC), C3 / C4 grasses fractions, major crops, phenology and soil data into a standard format for global (0.5° × 0.5° resolution) and regional (North American: 0.25° × 0.25° resolution) simulations. In order to meet the needs of MsTMIP, improvements were made to several of the original environmental data sets, by improving the quality, and/or changing their spatial and temporal coverage, and resolution. The resulting standardized model driver data sets are being used by over 20 different models participating in MsTMIP. The data are archived at the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC, http://daac.ornl.gov) to provide long-term data management and distribution.

Wei, Y., S. Liu, D.N. Huntzinger, A.M. Michalak, N. Viovy, W.M. Post, C.R. Schwalm, K. Schaefer, A.R. Jacobson, C. Lu, H. Tian, D.M. Ricciuto, R.B. Cook, J. Mao, X. Shi (2014) "The North American Carbon Program Multi-scale Synthesis and Terrestrial Model Intercomparison Project: Part 2 - Environmental Driver Data", Geoscientific Model Development, 7, 2875-2893, doi:10.5194/gmd-7-2875-2014.