中国陆地生态系统净初级生产力变化特征——基于过程模型和遥感模型的评估结果

The Changes of Net Primary Productivity in Chinese Terrestrial Ecosystem: Based on Process and Parameter Models

净初级生产力(NPP)作为生态系统物质与能量循环的基础,是区域和全球尺度碳循环和碳收支研究的重要组成部分。研究区域和全球尺度的净初级生产力主要依靠模型手段实现,过程和遥感模型是目前广泛使用的两种模型形式。本文搜集并整理了基于过程模型和遥感模型对我国陆地生态系统净初级生产力的模拟结果,分析了中国陆地生态系统净初级生产力的时间变化及对未来气候变化的响应特征,旨在对其进行综合评价。结果表明,中国陆地生态系统NPP平均为(2.828±0.827)PgC.a-1。1982-1998年的年际变化特征上,NPP平均每年增加0.027 PgC,年增长率为1.07%,总体上呈现在波动中逐年上升的趋势。不同植被类型的单位面积NPP总体表现为常绿阔叶林显著高于其他植被类型,但不同研究结果间变化范围很大;落叶针叶林、常绿针叶林和落叶阔叶林相差较小;农作物低于阔叶林,但高于针叶林;草地和荒漠均位于低值区,但前者显著高于后者。不同植被类型的NPP总量总体表现为农作物和草地位居前两位,两者之和高达各植被类型NPP总量之和的58.34%;除灌丛和常绿针叶林外,其余植被类型均不足总量的10%。在未来气候情景下,中国陆地生态系统NPP总体上可能表现为先增加后减小的趋势。

Net primary productivity（NPP） is a basis of material and energy flows in terrestrial ecosystems,and it is also an important component in the research on carbon cycle and carbon budget.At present,studies on NPP on regional and global scales mainly depend on model simulation,among which process and remote sensing models are widely used.In this paper,we analyzed the published NPP for Chinese terrestrial ecosystem and its response to future climate change which were computed by process and remote sensing models.The results revealed that the averaged NPP in Chinese terrestrial ecosystem was（2.828±0.827） PgC.a-1.Between 1982 and 1998,NPP tended to fluctuate but increased by 0.027 PgC.a-1 with an annual rate of 1.07%.Among different vegetation types,NPP per unit area was the maximum in evergreen broadleaf forests,which varied in a wide range among different researches;the values had a small discrepancy among deciduous needleleaf forests,evergreen needleleaf forests and deciduous broadleaf forests,and the value of croplands was lower than that of broadleaf forests,but higher than that of needleleaf forests;both grasslands and deserts had relatively low values,with the former having a significantly higher value than the latter.Furthermore,the total amount of NPP was the maximum in croplands followed by grasslands.The sum of both accounted for 58.34% of the gross.Except shrublands and evergreen needleleaf forests,all the other vegetation types had less than 10% of the gross.In the future climate scenarios,the NPP of Chinese terrestrial ecosystem might increase firstly,and then decrease.