Global and Regional Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) from SPOT-VGT and PROBA-V, 1999-present

The FAPAR quantifies the fraction of the solar radiation absorbed by live leaves for the photosynthesis activity. Then, it refers only to the green and alive elements of the canopy. The FAPAR value results directly from the radiative transfer model in the canopy which is computed instantaneously. It depends on the canopy structure, vegetation element optical properties, atmospheric conditions, and angular configuration. To overcome this latter dependency, a daily integrated FAPAR value is assessed. FAPAR is very useful as input to a number of primary productivity models which run at the daily time step. The FAPAR products are derived from SPOT-VGT and PROBA-V sensors.

光合有效辐射吸收比（FAPAR）用于量化活叶片进行光合作用时所吸收的太阳辐射占总辐射的比例。其仅指代冠层内绿色且存活的组织部分。FAPAR数值直接由冠层内的辐射传输模型瞬时计算得到，受冠层结构、植被组分光学特性、大气条件以及角度配置的影响。为消除角度配置带来的依赖性，通常会计算日积分FAPAR数值。FAPAR作为众多以日为时间步长运行的初级生产力模型的输入参数，具备极高的应用价值。FAPAR产品由SPOT-VGT与PROBA-V传感器反演获取。