Quantifying Feedbacks and Uncertainties of Biogeochemical Processes in Earth System Models
The overarching goals of this activity are to identify and quantify the feedbacks between biogeochemical cycles and the climate system, and to quantify and reduce the uncertainties in ESMs associated with these feedbacks. Through a comprehensive program of hypothesis-driven research, these goals will be accomplished by performing multi-model sensitivity analyses and comparisons with best-available observations and derived metrics. Investigations will focus on biogeochemistry–climate feedbacks associated with changes on interannual to decadal timescales (including ecological impacts of changes in disturbance regimes and climate extremes) and longer-term trends (including potential tipping points).
Important classes of observations used in the effort include observations of energy, carbon, and water from U.S. Department of Energy Ameriflux and Next Generation Ecosystem Experiments, National Aeronautics and Space Administration remote sensing observations of land and ocean ecosystem characteristics, National Oceanic and Atmospheric Administration and National Science Foundation atmospheric trace gas observations from aircraft and surface sites, above- and below-ground carbon inventories, atlases of three-dimensional ocean carbon and nutrient distributions compiled from shipboard observations, and syntheses and meta-analyses of terrestrial ecosystem manipulations of carbon dioxide, warming, nutrients, soil moisture, and tree cover.
Four objectives define the research focus of this activity:
- Development of new hypothesis-driven approaches for evaluating ESM biogeochemical processes using observations from site, regional, and global scales;
- Investigation of the degree to which contemporary observations can be used to reduce uncertainties in future scenarios, using an “emergent constraint” approach;
- Creation of an open source benchmarking software system that leverages the growing collection of laboratory, field, and remote sensing data sets for systematic evaluation of ESM biogeochemical processes; and
- Evaluation of the performance of biogeochemical processes and feedbacks in different ESMs participating in model intercomparison projects, including CMIP5 and CMIP6.
Please visit the project website for more detailed information: http://www.bgc-feedbacks.org/