Estimation of fraction of Absorbed Photosynthetically Active Radiation from multiple satellite data

Fraction of Absorbed Photosynthetically Active Radiation (FPAR) is a critical input parameter in many climate and ecological models. An accuracy of ±0.1 in FPAR is considered acceptable in the applications. However, most of current FPAR products, such as Moderate-Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR), do not fulfill the accuracy requirement yet. The objective is to develop a new radiative transfer model for FPAR estimation, with broadened surface reflectance database from the time series of twelve years´ reflectance data. The model proposed here could successfully identify growing season and the time series curve of estimated FPAR was smooth over years. The R² between estimated FPAR and in situ measurements was improved compared to existing FPAR products.