ABSTRACT
ABSTRACT: Earth observation systems provide high-quality tools to review the state of terrestrial surfaces at the global scale over long periods. In the special context of monitoring land degradation and desertification, long time series of remote sensing products are needed to evaluate the changes in terrestrial surfaces. As an example, plant photosynthesis in terrestrial environments can be documented from spectral measurements made in space. Advances in the understanding of radiation transfer, and the availability of high performance instruments, have led to the development of a new generation of geophysical products providing reliable, accurate information on the state and evolution of terrestrial environments. Specifically, a series of optimized algorithms has been developed and used to estimate the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) for a suite of recent instruments. This paper summarizes the methodology and performance of these FAPAR algorithms and presents various examples of applications showing an analysis of seasonal cycles and maps of vegetation activity anomalies in Europe and the Sahel.
