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

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.