An inversion method of fraction of absorbed photosynthetically active radiation which divided direct and diffuse radiation

Fraction of Absorbed Photosynthetically Active Radiation (FPAR) is the fraction of the incoming solar radiation in the Photosynthetically Active Radiation spectral region that is absorbed by a photosynthetic organism. This biophysical variable is directly related to the primary productivity of photosynthesis and some models use it to estimate the assimilation of carbon dioxide in vegetation. The solar radiation reaching to the canopy can be divided into direct radiation and diffuse radiation. The processes of two kinds of radiation are different. But a lot of retrieval models of FPAR did not consider this difference. In this paper, we established a FPAR inversion model which divided direct and diffuse FPAR. And MODIS LAI and surface albedo products were used as the model input data. And at the end of this paper, the inversion FPAR was verified with observation data and MODIS FPAR product.