Global Research Alliance on agricultural greenhouse gases - benchmark and ensemble crop and grassland model estimates

摘要: The Soil Carbon and Nitrogen Cycling Cross-cutting Group (Soil CN group) of the Global Research Alliance on Agricultural Greenhouse gases (GRA) promotes a coordinated activity across multiple international projects (e.g. MIP Models4Pastures FACCE-JPI https://www.faccejpi.com) to benchmark compare simulation models that simulate GHG emissions from arable crop grassland systems. Ten long-term experimental sites are studied covering variety climatic geographic conditions worldwide (Australia, Brazil, Canada, France, India, New Zealand, Switzerland, United Kingdom States). Twenty-four process-based different complexity have contributed modelling exercise in stages, each with access gradually more detailed data run evaluate multi-stage protocol. We present comparison model estimates production grain yield, gross primary production, above-ground net grazing or defoliation) vegetation leaf area index) outputs, as well ecosystem respiration, nitrous oxide, enteric methane) individual multi-model ensemble. found substantial discrepancies models, indicating considerable uncertainties regarding processes. show considerably reduced after calibration phenology data. approach also allowed for improved performance, according relative root mean square error bias performance metrics. Calibrated provide reliable basis testing mitigation options at sites.