中国陆地生态系统碳源/汇整合分析

国家尺度陆地生态系统碳收支及其循环过程的研究对于提升地球系统科学与全球变化科学的科技创新能力、提高我国参与应对全球气候变化国际行动和维护国家利益的话语权、保障国家生态安全和改进生态系统管理都具有重要意义。近年来，我国已经在气候变化与陆地生态系统碳循环领域开展了大量的研究工作，主要包括国家清查、生态系统模型模拟、大气反演等手段。然而，由于大尺度陆地生态系统碳源/汇的估算存在很大的不确定性，目前尚未形成国家尺度的陆地生态系统碳源/汇的整合分析。通过搜集已发表的关于中国陆地生态系统及其组分碳源/汇的59篇文献，整合国家清查、生态系统模型模拟、大气反演3种研究手段，分析中国陆地生态系统碳源/汇大小以及时间尺度上的动态变化。结果表明，在1960s-2010s期间中国陆地生态系统碳汇整体呈上升趋势，平均为（0.213±0.030）Pg C/a，其中森林、草地、农田和灌木生态系统碳汇分别为（0.101±0.023）Pg C/a、（0.032±0.007）Pg C/a、（0.043±0.010）Pg C/a和（0.028±0.010）Pg C/a。森林生态系统中的植被碳汇远大于土壤碳汇，然而这种格局在草地和农田生态系统却相反，而且1960s-2010s期间中国主要植被类型的生态系统碳汇总体上随时间呈增加趋势。融合多源数据（地面观测、激光雷达、卫星遥感等）、多尺度数据（样地尺度、站点尺度、区域尺度）以及多手段数据（联网观测、森林清查、模型模拟），有助于全面准确地评估中国陆地生态系统碳源/汇及其对气候变化的响应。

Integration analysis of the carbon sources and sinks in terrestrial ecosystems, China

Estimating the national-scale terrestrial ecosystem carbon budget and their response to climate change is important to enhance the scientific and technological innovation capabilities of earth system science and global change science, to increase China''s right to speak in international action to respond to global climate change, and to improve national ecological security and ecosystem management. The study of terrestrial ecosystems'' carbon sources and sinks at the national scale is not only an urgent need to effectively mitigate greenhouse gases and tackle climate change, but also a task for the development of earth system science and global change science. In recent years, China has carried out a lot of research in the fields of climate change and terrestrial ecosystem carbon cycle, mainly using national inventory, ecological modelling, and atmospheric inversion. However, there is large uncertainties in the estimating large-scale terrestrial ecosystem carbon sources and sinks and a comprehensive analysis of carbon sources and sinks in China''s terrestrial ecosystems has not yet been formed. In this study, we collected 59 published literatures on China''s terrestrial ecosystems and their components, to analyze the magnitudes and dynamics of carbon sources and sinks in China''s terrestrial ecosystems by integrating the three methods of national inventory, ecological modelling, and atmospheric inversion. The results found that from 1960s to 2010s, China''s terrestrial ecosystem carbon sink showed an increasing trend, with an average of (0.213±0.030) Pg C/a, of which forest, grassland, cropland and shrub ecosystems were (0.101±0.023) Pg C/a, (0.032±0.007) Pg C/a, (0.043±0.010) Pg C/a and (0.028±0.010) Pg C/a, respectively. Vegetation carbon sinks in forest ecosystems were much larger than soil carbon sinks, but this pattern was reversed in grassland and cropland ecosystems. Moreover, the carbon sinks of the major vegetation types in China showed an increasing trend from 1960s to 2010s. Therefore, we recommend that the fusion of multi-source data (ground observation, lidar, and satellite remote sensing), multi-scale data (sample scale, site scale, and regional scale), and multi-method data (networked observation, national inventory, and modeling) to reduce the uncertainties in the large-scale terrestrial ecosystem carbon budgets, which is helpful for comprehensive assessment of carbon sources and sinks in China''s terrestrial ecosystem and its response to climate change.