In-situ networks on test-sites in support of space earth observations

Acknowledged and justified is the recognition of remote sensing as a powerful tool in land cover/land use monitoring for a large number of purposes ranging from agricultural practices to global ecology and environment protection. Data collected and information created from Earth observations constitute critical inputs to the sustainable management of the Earth - providing evidence for informed decision-making. However, policies on the environment often suffer by having to rely on information that is fragmentary and of uneven quality and value despite of the considerable progress that has been made in space-borne observation systems and information technologies. Currently, the remote sensing community is recognizing again, in a more complex and systematical way, the indispensable necessity of ground-truth information in support of satellite Earth observation missions. In order the remote sensing techniques to be widely transferred to operative applications, data accuracy and information reliability is critical. Algorithms and quantitative models for estimating various land surface variables from remotely sensed observations need to be validated using geo-reference data. Supporting and raising the capacity of remote sensing investigations encompasses the implementation of a wide range of information sources, making full use of ground-based in-situ monitoring as well as of airborne surveys and space-based observations. In this context the paper presents a vision on the objectives, the infrastructure and the functioning of in-situ networks for data acquisition on target selected test-sites with the aim to enhance remote sensing scientific and modelling capacities and to meet the need for multidisciplinary research and multipurpose data application relying both on technology developments and data accuracy. The paper aims also at rising the interest in international networking and collaboration.