Estimation Of Net Primary Productivity Based On Improved Light Use Efficiency Model In Gannan

NPP is a direct product of carbon exchange between the biosphere and the atmosphere and the largest component of atmospheric carbon exchange,is also considered the main reason for the seasonal variation of atmospheric CO2 concentration.It can reflect the true productivity of terrestrial vegetation,as well as is infrastructure of the terrestrial ecosystems substance cycle energy.NPP study has important implications for regional and global carbon cycle.This article established the Gannan region NPP estimation model based on the use of solar energy utilization of remote sensing data model and simulate the NPP and the multiple factors that influence the NPP.The concluusion are as followiing:(1)The Improved Light Use Efficiency Models can simulated NPP well and be used simulate NPP in short time scale and large area.(2)In different altitude gradients,the light use efficiency,the absorbed photo-synthetically active radiation,respiration and NPP first increases then decreases with altitude,and the altitude of area that contain the maximum and mininum is different.(3)In different basins,the distribution of the light use efficiency and the absorbed photosynthetically active radiation,the respiration andthe NPP is simi-lar,the order of the value from high to low in various basin were Baishui>Bail ong>Taohe>Huanghe>Daxiehe.(4)The light use efficiency,the absorbed photosynthetically active radiation, the respiration and the NPP first increases then decreases with time,the value of all the factor is minimum in January and is maximum in July.(5)The total NPP is maximun at 1.865×1013 g·C in 2014 and the minimun in 2012 in gannan.