A new FAPAR retrieval model for continuous vegetation

The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) is the fraction of incoming solar radiation that is absorbed by green vegetation in the spectral range from 400 nm to 700 nm. FAPAR reflects the energy absorption ability of vegetation canopy. It is a critical input in many land surface models, such as crop growth models, net primary productivity models, climate models and ecological models. Existing models for FAPAR retrieval are complex and difficult to retrieve, most of them cannot be used under cloudy weather. In this paper, a new quantitative FAPAR retrieval model considering the diffuse skylight and multiple scattering between canopy and background is introduced to retrieve FAPAR of vegetation canopy. The model was used to continuous vegetation and was validated by Monte Carlo (MC) simulation and field tests. The conclusion shows that the error is less than 0.32%.