本项目以北半球典型陆地生态系统碳循环研究为主线，依托ChinaFLUX和CERN的基础研究平台，通过与美国（AmeriFlux）和欧洲(CarboEurope)通量观测网络的合作与交流，提高对陆地生态系统温室气体联网综合观测的关键技术；利用数据挖掘的方法整合分析温室气体通量及相关数据，揭示以碳循环为核心的关键地表过程的生物地理格局，阐明气候变化对碳循环和相关生态系统过程的影响；通过数据-模型耦合建立模型基准评估体系，评价IPCC用到的三个陆地模型（CoLM, CLM和ORCHIDEE）对中、美和欧洲三个区域碳收支预测的不确定性，优化模型参数，提高模型模拟的准确性，为探讨典型区域碳循环过程的适应性管理提供理论依据和技术途径。

By integrating the three networks: ChinaFlux, AmeriFlux, and CarboEurope, this international collaborative research is designed to conduct network-to-network integrative research on carbon cycle studies, and to evaluate and improve global land models by benchmark analysis and data assimilation, so that the terrestrial carbon budget over the whole northern hemisphere and its roles in global carbon cycle can be synthetically quantified and understood. Based on on-going multiple-scale measurements of carbon flux and storage, and data-model fusion and data assimilation techniques, this collaborative research will quantify and predict carbon source and sink dynamic and their responses to climate change, explore the carbon management measures and strategies suitable to the regions, and stress the scientific exchange on the carbon flux issues among research communities. Data-model fusion approach will be used to benchmark some representative land models (e.g. CoLM, CLM, ORCHIDEE) and constrain parameters as well as quantify model uncertainty. The central theme of this project will be the integration of data, information, and knowledge of carbon cycle across the northern hemisphere by network-to-network collaborative effort of scientists from China, American and European. In addition, the project aims to encourage and train more young researchers through cooperative activities described below.