地球系统模式中土壤微生物呼吸的评估及改进

全球气候与环境变化已成为不争的事实，碳循环模拟作为地球系统模式中的重要环节，对于我们理解大气二氧化碳浓度变化对气候与环境的影响至关重要。土壤微生物呼吸作为陆地上仅次于光合作用的陆气碳交换过程，在当今观测和模式中均存在很大的不确定性。本项目研究拟采用理论、统计分析和数值模拟相结合的方法评估当前最先进的地球系统模式对大尺度土壤微生物呼吸的模拟效果。围绕异氧呼吸过程针对目前地球系统模式对地下生物地球化学过程模拟的理论框架的难点和重要科学问题作深入研究，如：异氧呼吸对地表温度、土壤湿度和土壤有机氮含量的敏感性、植被凋落物和细根渗出液的激发作用、根圈效应等。通过以上研究最终提出一个适用于地球系统模式的土壤微生物呼吸的普适方案，并应用于中科院地球系统模式的设计。

With the fact of observed global climate and environmental changes, carbon cycle modelling, as an important component of the Earth System models (ESMs), is critical to our understanding of the influences of evolution of atmospheric carbon dioxide concentration on climate and environment. As the second largest carbon flux after photosynthesis in the carbon cycle, micorbial respiration is very uncertain both in observation and models. By using the theorectical and statistical analysis, and numerical simulation method, this project aims to evaluate the broad-scale parameterization of microbial respiration in the state-of-art ESMs nowadays. Then we plan to investigate the general framework for the integrated underground biogeochemical processes with focus on some important and frontier scientific issues. For example, the sensitivities of heterotrophic respiration to the surface temperature, soil moisture, and the soil nitrogen content; the priming effects of substrates from litters and fine roots; rhizosphere effect; etc. Based on the above studies, a more sophisticated approach to simulate microbial respiration in the ESMs will be developed, and will be applied to the design of integrated CAS-Earth System Model.