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Acta Prataculturae Sinica ›› 2013, Vol. 22 ›› Issue (5): 220-228.DOI: 10.11686/cyxb20130526

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Algorithm improvements for two important parameters of FPAR and maximum solar energy utilization efficiency

WANG Bao-lin1,2,WANG Jing-jie2,YANG Yong2,CHANG Shu-juan2, CHEN Xi-mei2, LIU Ai-jun1,2   

  1. 1.Agricultural College of Inner Mongolia Nationalities University, Tongliao 028043, China;
    2.Inner Mongolia Institute of Grassland Survey and Planning, Hohhot 010051, China
  • Online:2013-10-20 Published:2013-10-20

Abstract: Photosynthetically active radiation and solar energy utilization efficiency are two of the most important parameters in NPP (net primary productivity) simulation. The solar effective radiation value of key phenological phases for typical steppe was tested using the light quantum instrument, and two models for FPAR (fraction of photosynthetically active radiation) estimation according to correlation between NDVI (normalized difference vegetation index) and FPAR were established. The correlations between measured and estimated FPAR values were significant, and there was no significant difference between the two groups value of model estimation. Therefore, mean values of estimated FPAR were calculated, and nested with NASA (national aeronautics and space administration)-FPAR products, to form a complete FPAR spatial distribution map of grassland in China. In addition, the study also adjusted maximum solar energy utilization efficiency of 18 categories of grassland in China based on normalized difference vegetation index (NDVI) and leaf area index (LAI). The result also showed that adjustment of maximum solar energy utilization efficiency could improve accuracy (85.71% at larger scale) of NPP estimation after inputting the NPP model.

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