摘要
陆地生态系统的净生产力 (NEP)是生态系统净初级生产力 (NPP)和异氧呼吸 (Rh)之差。在全球尺度上 ,反映NPP和Rh之差的NEP直接揭示陆地生态系统与大气系统之间的二氧化碳交换 ,即碳平衡 ,因此 ,意义重大。文章简短回顾了关于中国陆地生态系统碳平衡的研究状况。由于植物根部呼吸很难从土壤表面总二氧化碳 (CO2 )通量中分开 ,因此直接从野外测量土壤异氧呼吸几乎是不可能的。虽然由于像诸如火灾、森林砍伐、土地利用变化及气候和大气变化等干扰因素 ,全球陆地生态系统很大程度上处于非平衡态 ,利用生态系统在平衡态时NPP等于Rh这一事实 ,我们估算了全球和中国森林生态系统的土壤异氧呼吸。利用遥感和地面的NPP观测数据 ,我们也估算了中国森林生态系统逐月的净生产力 (1982— 1998)。NPP的估算主要采用NOAA卫星AVHRR 8km的NDVI数据 ,结合地面气候数据完成。土壤呼吸是通过地面观测数据与温度和降水的关系得到的。在此基础上我们得到了中国陆地生态系统在过去近 2 0年中碳的动态变化 ,并给出了初步结果。
In this paper, we briefly review some of the research efforts that are related to the carbon balance of China. Carbon balance is characterized by the net ecosystem productivity (NEP), the difference between net primary productivity (NPP) and the heterotrophic respiration, namely the decomposition of dead organic matter by soil microbes. Direct field measurement of Rh is rare because separating root respiration (Rr) from the total soil surface CO 2 efflux is very difficult.At the equilibrium state, ecosystem net primary productivity (NPP) equals Rh.The current global terrestrial ecosystems are most likely at non-equilibrium state due to various disturbances,such as fire,deforestation,and land-use change, as well as climate and atmospheric changes.At the global scale, the difference between NPP and Rh is of great interest because it indicates the capacity of terrestrial ecosystems absorbing/releasing CO 2 from/to the atmosphere. We report in this paper our initial attempts towards the determination of carbon balance of China based on a new technique for estimating soil Rh. Preliminary results obtained for China’s forest ecosystems are presented.
出处
《地学前缘》
EI
CAS
CSCD
2002年第1期55-61,共7页
Earth Science Frontiers
基金
国家自然科学基金资助项目 ( 4 982 5 5 11)
国家重点基础研究发展规划项目 ( 2 0 0 1CB30 940 5 )
