The version 3 CYCLOPES algorithms assess the FAPAR by inversion of the radiative transfer model SAIL (Verhoef, 1984) using neural network which considers as input the solar zenith angle at 10:00 local time and the normalized nadir reflectances in red, NIR and SWIR wavebands. This methodology, defined by the CSE team of INRA Avignon, is applied to VEGETATION data. More details about the CYCLOPES algorithms are given in Baret et al. (2007).

Examples below show the low values of FAPAR over the sahelian ecosystem in Niger (left) and high values of FAPAR over the green vegetation of Eastern coast of North America (right).

CYCLOPES FAPAR over Niger (left) in September 2001 and the North East coast of USA (right) in June 1999.

The LAI, FCover, and FAPAR (1999 - 2003) are included in the same product called "Biophysical", which can be downloaded with a readme file. They are provided in tiles of 10°x10° covering the whole globe in plate-carrée projection. The map locating the tiles can be downloaded.
Furthermore, LAI, FAPAR, and FCover are extracted over 323 sites of the BELMANIP database (Baret, et al., 2006) used for validation. These extractions covering about 50km*50km can be downloaded, with a list and description of sites.

The CYCLOPES FAPAR validation relies on :
  the intercomparison with existing products generated in the frame of other projects (MODIS, ECOCLIMAP)
  the comparison with in-situ measurements collected over the experimental sites of ground networks (VALERI, BIGFOOT,...), and upscaled using high resolution satellite images (below).
The results are presented in Weiss et al. (2007).

Comparison of CYCLOPES and MODIS FAPAR with ground measurements (from Weiss et al., 2007).

Baret, F., O. Hagolle, B. Geiger, P. Bicheron, B. Miras, M. Huc, B. Berthelot, f. Nino, M. Weiss, O. Samain, J.L. Roujean, and M. Leroy, LAI, FAPAR, and FCover CYCLOPES global products derived from Vegetation. Part 1 : principles of the algorithm, Remote Sensing of Environment, 110:305-316, 2007.

Baret, F., J.T. Morisette, R.A. Fernades, J.L.Champeaux, R.B. Myneni, J. Chen, S. Plummer, M. Weiss, C. Bacour, S. Garrigues, and J. Nickeson, Evaluation of the representativeness of Networks of sites for the Global Validation and Intercomparison of Land Biophysical Products : Proposition of the CEOS-BELMANIP, IEEE Transactions on Geoscience and Remote Sensing, vol44, 7, 1794-1803, July 2006.

Verhoef, W., Light scattering by leaf layers with applications to canopy reflectance modelling : the SAIL model, Remote Sensing of Environment, 16:125-141, 1984.

Weiss, M., F. Baret, S. Garrigues, and R. Lacaze, LAI and FAPAR CYCLOPES global products derived from Vegetation. Part 2 : validation and comparison with MODIS C4 products, Remote Sensing of Environment, 110:317-331, 2007.