Introduction - Vegetation Programme
The VEGETATION Programme is developed jointly by France, the European Commission, Belgium, Italy and Sweden. The first satellite component (VEGETATION 1) of the programme was launched on 24th March 1998 onboard SPOT 4, while the second instrument was launched onboard SPOT 5 on 4th May 2002. They deliver measurements specifically tailored to monitor land surfaces' parameters with a frequency of about once a day on a global basis and a medium spatial resolution of one kilometre. The associated Centralised Ground Segment processes instrument measurements to offer standard products to the general users' community. The entire system complements the existing high spatial resolution capabilities of the SPOT series, providing similar and simultaneous spectral measurements in the visible and short wave infrared domains. Instruments original features and its situation onboard SPOT platforms allow users to have access to :
- robust and simple multitemporal measurements of the solar reflection domain radiative properties of land areas,
- a continuous and global monitoring of the continental areas either through the centralised archiving and processing facility, or, for local or regional studies, using local receiving stations,
- long term data sets with accurate calibration and positioning, continuity and consistency through the renewal of the system on further satellites,
- multiscale approaches of surface parameters and processes using simultaneous measurements acquired through the VEGETATION instrument and the High Resolution instruments of the SPOT series.
The decision to undertake this programme is the result of the development of many studies and projects during the last ten years : the use of remote sensing data in operational programmes or in projects which should lead to operational applications strongly increased to the point where data quality and availability is clearly becoming a limitation. As working groups, users' communities and international programmes were expressing their needs for increasing details, the idea to take the opportunity to embark upon a dedicated and definitely operational mission onboard SPOT 4 was favourably supported by the partners of the Programme. The needs of the sectoral policies of the European Commission (for the management of productions in agriculture, for forestry and environmental monitoring ) and of the national partners as well as of the large international programmes related to the study of Global Changes were synthesised by an International Users Committee and became the basis for the technical development of the entire system.
The strong commitment of the European Commission is also a clear sign that the mechanisms by which remote sensing systems are designed and operated are changing : as methodologies to use remote sensing data become more and more adapted to a regular and operational need, the decision to undertake such a development is now also in the hands of the users and do not stay only on the sole responsibility of space agencies. The development of VEGETATION, the structure of the Programme and its achievements is a full scale test by which the new mechanisms are exemplified. Its overall objectives must nevertheless remain a long term commitment to provide useful data to an identified user's community.