Operational Service Demonstration for Global Land-Cover Mapping: The GlobCover and GlobCorine Experiences for 2005 and 2009

In view of the increasing concern over the functioning of the earth system, land-cover observation at a global scale is crucial in assessing the impacts of climate change, preserving biodiversity, and understanding biogeochemical cycling. Various global land cover maps derived from satellite imagery have been produced. Since the early nineties the sensors have largely evolved in term of spatial resolution, frequency of aquisition as well as the pre-processing what allowed improving the quality of the optical time series but some limitations are still observed. First, some datasets were not yet fully satisfying and the global land-cover community strongly pushed for improving global land-cover assessments. Second, most global land-cover efforts were one-time exercises that did not allow repeated map production. Finally, their spatial resolution (1 km at best) was not fine enough to deal adequately with the large landscape heterogeneity. As regards the latter point, the recent availability of the MERIS instrument, with its fine spatial resolution, offered a new opportunity. Building on the success of the GLC2000 project, the European Space Agency (ESA) launched in 2005 the GlobCover initiative. The current needs of the global community are not only to supply a product but—equally important—to develop an operational service that enables the regular and timely delivery of consistent global land-cover maps. Such a service should also allow interactions with users and iterative improvements of follow-ups. Automation, timeliness, and transparency are the three main objectives and the most important prerequisites for a service to be included in the line of Global Monitoring for Environment and Security (GMES) Service Elements as defi ned by the European Union (EU). Meeting those requirements, the GlobCover and GlobCorine systems can be considered the precursor of a global and a regional land-cover service, respectively. These two systems are described in this chapter as well as the MERIS instrument, the validation results and lessons learned.JRC.H.4-Monitoring Agricultural Resource