鄱阳湖流域碳水循环对植被恢复的响应

项目名称： 鄱阳湖流域碳水循环对植被恢复的响应

项目编号： No.40871240

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 建筑科学

项目作者： 居为民

作者单位： 南京大学

项目金额： 40万元

中文摘要： 本项目以鄱阳湖流域为研究区，运用遥感技术跟踪植被恢复动态；利用通量观测数据分析典型生态系统碳水通量变化特征并优化模型参数；利用森林清查和遥感数据研究了森林生物量和郁闭度的变化趋势；利用多源遥感数据构建了长时间叶面积指数（LAI）数据集，驱动BEPS模型，模拟分析碳水通量的时空变化特征，评价了森林类型和年龄对蒸散（ET）的影响；探讨了研究区内净初级生产力(NPP)的空间变异特征；构建了考虑固碳效益的土地利用决策模型。 结果表明，基于4尺度几何光学模型的LAI反演方法适合于在研究区应用；近年来吉安市的森林生物量和郁闭度都在上升；森林类型和年龄都是ET的重要影响因子；BEPS模型中计算光合与的ET的关键参数存在明显的季节和年际变化；鄱阳湖流域的总初级生产力（GPP）、NPP和ET 由北向南递增，近30年来该地区陆地生态系统是一个碳汇，1981-2004年期间GPP和NPP呈现明显上升趋势，主要原因是植被恢复，但是2005年后，由于气候异常，碳汇减小；ET与NPP和GPP正相关，但与NEP关系不密切。研究成果对全面评价植被恢复的生态效益和深化碳循环研究具有重要的科学和现实意义。

中文关键词： 全球变化；碳水耦合循环；植被恢复；森林年龄；机理性生态模型

英文摘要： Terrestrial carbon and water cycles are interactively linked. They are the core in the cycles of materials and energy on the ground surface and both are affected by environmental factors and vegetation dynamics. This study takes the PoYang Lake watershed as the study area to study changes of carbon and water fluxes and underlying driving forces. Remote sensing technique was employed to track vegetation dynamics. Measured fluxes were used to study the characteristics of carbon and water cycles and to optimize model parameters. Inventory and remote sensing data were applied to analyze the changes of biomass and canopy coverage of forests. Long term LAI data was generated using different sources of remote sensing data and used to drive the BEPS model for studying the spatial and temporal patterns of carbon and water fluxes. The influences of land cover and forest ages on evapotranspiration (ET) were also assessed. A system based on the Arc-GIS platform was developed for scientifically making decision on land use with the consideration of the benefit of carbon sequestration. It shows that the model based on 4-scale model is suitable for inversing LAI in the study area. Both biomass and forest canopy coverage have been increasing in recent years. Land cover and forest age have considerable effects on ET. The optimized key parameters in the BEPS model crucial for the simulations of photosynthesis and ET shows noticeable seasonal and interannual variations. Gross primary productivity (GPP), net primary productivity (NPP) and ET show increasing trends from the north to the south. The terrestrial ecosystems in the PoYang Lake watershed act as a carbon sink in recent 30 years. NPP and GPP increased significantly during the period from 1981 to 2004, mainly due to the restoration of vegetations. However, the carbon sink shrank after 2005 because of abnormal climate. GPP and ET are both positively correlated with ET. Net primary productivity (NEP) shows very weak linkage with ET. The findings from this study are scientifically valuable for assessing the ecological benefit from vegetation restoration and enhancing study on terrestrial carbon cycle.

英文关键词： Global change; coupling between water and carbon cycles; vegetaion restoration; forest age; process-based ecological model