Leaf Area Index

sample thumbnail of surface reflectance image

LAI is deﬁned as the one-sided green leaf area per unit ground area in broadleaf canopies and as half the
total needle surface area per unit ground area in coniferous canopies. FPAR is the fraction of photosynthetically
active radiation (400-700 nm) absorbed by green vegetation. Both variables are used for calculating surface
photosynthesis, evapotranspiration, and net primary production, which in turn are used to calculate terrestrial
energy, carbon, water cycle processes, and biogeochemistry of vegetation. Algorithm refinements have improved
quality of retrievals and consistency with field measurements over all biomes, with a focus on woody vegetation.