Validation of GMES Geoland-2 global biophysical variables (GEO VERSION1) products

This study investigates the scientific quality of the first version of global biophysical products (FCover, LAI, FAPAR) developed in the Geoland-2 /BioPar Core Mapping Service, namely GEOV1. These products based on SPOT/VEGETATION data were built on MODIS and CYCLOPES products while reconciling their differences. The quality assessment strategy follows the CEOS/WGCV Land Product Validation guidelines. The spatial and temporal consistency of GEOV1 products is assessed by intercomparsion with existing global products (MODIS C5, CYCLOPES V3.1, GLOBCARBON V2, JRC FAPAR) over a global network of homogeneous sites (BELMANIP-2) over two years period (2003-2005). The accuracy of GEOV1 is evaluated against a number of available ground truth maps. Several criteria of performance were evaluated, including spatial distribution, missing values, magnitude of retrievals, temporal variations, smoothness, precision and accuracy. Our results show that GEOV1 products present reliable spatial distribution, smooth temporal profiles, stable from year to year, reliable magnitude for bare areas and dense forest, and the best performance with ground-based maps. GEOV1 outperforms the quality of existing global products in most of the examined criteria, and constitutes a step forward in the development of global biophysical variables in the framework of Geoland-2.