Elucidation of the Earth envimnmental cbange mechanism by satellite remote sensing and Earth system models

为了阐明地球系统的环境变化机制，我们将卫星遥感与地球系统模型相结合，重点研究生物圈与气候的相互作用。我们建立了一个简单的地球系统模型，将大气-海洋相互作用系统中的能量和碳循环耦合起来，发现当深海二氧化碳分压小于大气分压时，就会发生振荡。研究了全球变暖对陆地生物圈碳吸收的影响：全球生态系统净产量（NEP）不仅受到生物圈二氧化碳施肥和土壤分解的温度依赖性的影响，还受到净初级生产量（NPP）和土壤分解速率的温度依赖性的影响。以卫星观测资料为输入，建立了新的陆地生态系统模型BEAMS，分析了20世纪80年代以来全球NPP的变化。利用海洋-大气耦合环流模式（GCM）研究了喜马拉雅-青藏高原（HT）对亚洲季风发生的影响，发现喜马拉雅-青藏高原（HT）的存在是夏季北半球副热带高压区形成的重要条件。利用卫星遥感技术，研究了20世纪80年代以来中国陆地植被时空变化与气候的相互作用。研究发现，厄尔尼诺现象对各类型陆地植被的负面影响主要是由于降水减少，并且厄尔尼诺现象与陆地植被活动之间存在时滞。

In order to elucidate the enviromnental change mechanism in the Earth system, we carried out this research by combining satellite remote sensing and Earth system models with a focus on the interactions between the biosphere and climate. We developed a simple Earth system model which couples energy and carbon cycles in the atmosphere-ocean interactive system, and found that the oscillation occurs when the partial pressure of carbon dioxide in the deep ocean is smaller than that of the atmosphere. We also developed a meridional one-dimensional Earth system model of a coupled energy and carbon cycles, and investigated the effect of global warming to carbon uptake by the terrestrial biosphere : The global net ecosystem production(NEP)is greatly affected not only by the biosphere carbon dioxide fertilization and temperature dependency of soil decomposition but also by temperature dependency of net primary production(NPP)and soil decomposition rate. We developed a new terrestrial ecosystem model named BEAMS, and analyzed the global NPP variations since 1980's by using satellite observation data as input.We investigated the effect of the Himalaya-Tibetan Plateau(HT)on the onset of Asian monsoon with the coupled ocean-atmosphere General Circulation Model(GCM), and found that the existence of HT is an important condition to form the sub-tropical high atmospheric pressure zone of the northern hemisphere in summer. Interaction between the spatial and temporal variations of terrestrial vegetation and climate since 1980's was studied by using satellite remote sensing. We found that El Nino gives a negative impact to all types of the terrestrial vegetation mainly due to precipitation decrease, and there are time lag between El Nino and the terrestrial vegetation activities.