CYCLOPES is a European Union FP5 project, which has benefited also from additional funding from CNES, Région Midi-Pyrénées, and Réseau Terre et Espace.

Coordinated by INRA Avignon, CYCLOPES is fully perfomed in the frame of the POSTEL Thematic Centre. The Expertise Centres define the algorithms :

• SI/MO team of Cnes : cloud detection (with the support of Noveltis), atmospheric correction, residual clouds and aerosol filtering.
• MATIS team of CNRM : normalisation of directional effects
• CSE team of INRA Avignon : estimation of biogeophysical variables (LAI, FAPAR, FCover). These algorithms are described in Baret et al., (2007).

The Service Centre has developed the operational processing lines, performed the production, and disseminates the products to the scientific community.

CYCLOPES products (normalized surface reflectances, LAI, fAPAR, FCover) are derived from data acquired by the VEGETATION sensor. They have a global spatial coverage with a 1 km resolution. They cover the period 1999-2007 with a time step of 10 days.

CYCLOPES LAI and FAPAR have been validated by comparison with MODIS products and with ground measurements. The results are presented in Weiss et al., (2007). Furthermore, CYCLOPES LAI participates in an intercomparison exercice of existing global LAI products (CYCLOPES, ECOCLIMAP, GLOBCARBON, MODIS), coordinated by NASA/GSFC in collaboration with POSTEL and other products providers. First results of this work have been presented at the Global Land Vegetation Monitoring workshop in Missoula (August 8-10, 2006). The full study, described in Garrigues et al., 2008, concludes that the CYCLOPES LAI shows the best spatio-temporal consistency, and compares the best to the spatialized ground measurements (figure below) (VALERI, BIGFOOT, etc...), although the LAI level is a little bit low over the densest vegetation.

Comparison of CYCLOPES, ECOCLIMAP, GLOBCARBON, and MODIS LAI with spatialized ground measurements collected over various vegetation types : crop (red), grass (orange), Evergreen Needleleaf forest (light green), Evergreen Broadleaf Forest (dark green), and Mixed (ENF+DBF) Forest (magenta) (from Garrigues et al., 2007) .

Users have been identified in the framework of CYCLOPES project to test the usefulness of products for two applications linked to climate change :

• UCL : detection of land cover change and land use change
• MPI-Jena and MPI-Hamburg : carbon cyle modelling

Other applications use the CYCLOPES products. CNRM has compared the LAI simulated by the ISBA-A-gs land surface model (Calvet et al, 1998, 2004, 2008) over South-West of France for 3 years. This study demonstrated that large differences between the existing satellite LAI products and the ISBA-Ags simulations were a powerful indicator of the main model shortcomings (Brut et al., 2009). The particularly large difference in leaf onset (figure below) for C3 natural herbaceous vegetation permitted to identify a weakness of the model which was confirmed by in-situ observations.

Differences in leaf onset (days) between the ISBA-A-gs model simulations and (top) CYCLOPES and (bottom) MODIS satellite data for 2001, 2002 and 2003. (from Brut et al., 2009)

We can also mention some LTHE activities performed in the frame of AMMA project. The CYCLOPES LAI is one input of the ISBA (Noilhan et Planton, 1989) surface scheme in the C-MEB model (Pellarin et al., 2006a) to simulate the microwave emission of a scene. The simulated Brightness Temperature (TB) is then compared to the TB derived from the AMSR-E sensor (below). The study, which aims to elaborate a regional high resolution mapping of soil moisture, was performed over the Niger (Pellarin et al., 2006b), and can be extended to Benin and Mali.

Brightness Temperature (TB) simulated by the C-MEB model at 1km resolution (left). Re-gridded to 25km resolution (centre), it is compared to AMSR-E TB (right) (from Pellarin et al., 2006b).

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.

Brut, A., C. Rudiger, S. Lafont, J.-L. Roujean, J.-C. Calvet, L. Jarlan, A.-L. Gibelin, C. Albergel, P. Le Moigne, J.-F. Soussana, K. Klumpp, D. Guyon, J.-P. Wigneron, and E. Ceschia, Modelling LAI at a regional scale with ISBA-A-gs : comparison with satellite-derived LAI over southwestern France, Biogeosciences, 6, 1389-1404, 2009.

Calvet, J.-C., J. Noilhan, J.-L. Roujean, P. Bessemoulin, M. Cabelguenne, A. Olioso, and J.-P. Wigneron, An interactive vegetation SVAT model tested against data from six contrasting sites, Agricultural Forest Meteorology, 92, 73-95, 1998.

Calvet, J.-C., V. Rivalland, C. Picon-Cochard, and J.-M. Guehl, Modelling forest transpiration and CO2 fluxes : response to soil moisture stress, Agricultural Forest Meteorology, 124(3-4), 143-156, 2004.

Calvet, J.-C., A.-L. Gibelin, J.-L. Roujean, E. Martin, P. Le Moigne, H. Douville, and J. Noilhan, Past and future scenarios of the effect of carbon dioxide on plant growth and transpiration for three vegetation types of southwestern France, Atmospheric Chemistry and Physics, 8, 397-406, 2008.

Garrigues, S., R. Lacaze, F. Baret, J.T. Morisette, M. Weiss, J. Nickeson, R. Fernandes, S. Plummer, N.V. Shabanov, R. Myneni, W. Yang, Validation and Intercomparison of Global Leaf Area Index Products Derived From Remote Sensing Data, Journal of Geophysical Research, 113, G02028, doi:10.1029/2007JG000635, 2008.

Noilhan, J, and S. Planton, A simple parameterization of land surface processesfor meteorological models, Monthly Weather Review, 117, 536-549, 1989.

Pellarin, T., Y.H. Kerr, J.-P. Wigneron, Global simulation of brightness temperatures at 6.6 and 10.7 Ghz over land based on SMMR data set analysis, IEEE Transactions on Geoscience and Remote Sensing, vol.44, Issue 9, pp 2492-2505, 2006a.

Pellarin, T., J.-M. Cohard, J.-P. Laurent, L. Descroix, High resolution soil moisture mapping using AMSR-E brightness temperatures over the Niger site of the AMMA project, RAQRS Symposium, Valencia, 2006b

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.