中国陆地碳汇的分布及相关过程的研究

Recent studies have shown that terrestrial ecosystems are large carbon sinks for atmospheric CO2 cencentration in the Northern Hemisphere; however, the size and location remain uncertainty.In this project, we used terrestrial net primary productivity (NPP) that is derived from an.ecological process model, as an indicator of the carbon sinks, and time series datasets of normalized difference vegetation index (NDVI) and paired ground-based information on.vegetation, climate, soil, and solar radiation as data inputs, to explore the size and distribution of the carbon sinks in China’s land ecosystems. The results showed that NPP of China’s terrestrial ecosystems had increased significantly from 1.56 PgC/yr in the early 1980s to 1.84 PgC/yr in the.late 1990s, with an annual increase rate of about 1%. The increased NPP is critical for explaining increased carbon sinks in the northern latitudies. Generally, interannual variability of NPP corresponded to changes in climates; however, there was a time lag between changes in NPP and.climates. The trends of NPP over time showed large spatial and temporal heterogeneity,corresponding to biome structures, landuse changes, and regional climate attributes. The increased国家自然科学基金资助项目结题报告4NPP was primarily led by an advanced growing season for broadleaf evergreen forest, needle-leaf evergreen forest, and needle-leaf deciduous forest, whilst that was mainly due to enhanced.vegetation activity (amplitude of growth cycle) during growing season for broadleaf deciduous forest, broadleaf and needle-leaf mixed forest, broadleaf trees with groundcover, perennial.grasslands, broadleaf shrubs with grasslands, tundra, desert, and cultivation. Rapid urbanization.has led a significant reduction in NPP in east coastal regions, while increased agricultural activities have caused a pronouncing increase in NPP in farmlands. In abundant rainfall areas,.rising air temperature led to an increase in NPP while increased precipitation caused a decrease in.NPP. In less rainfall regions, increased precipitation increased NPP significantly.The results mentioned-above have provided useful parameters for evaluating carbon.acculumations and carbon sinks/sources of China’s terrestrial ecosystems.

在我国6个典型森林和草地生态系统类型中，设置样地，进行碳平衡参数的观测；基于空间清晰的过程和统计模型，采用翔实、可靠的地面实测资料，进行我国陆地碳库及CO2源汇功能的定量评估。将丰富生态系统生态学内容，并为我国相关的国际环境外交谈判提供技术支撑。