April 17, 2015

POSTEL Products

The images of Vegetation 1 & 2 sensors are the main data processed by the POSTEL thematic center over land surfaces within the FP5/CYCLOPES project of the ground bio-geophisical properties and continental vegetation cartography. CYCLOPES, funded by the European Union within the 5th PCRD aims to develop, validate and produce the Leaf Area Index (LAI) at global scale, the PAR fraction absorbed (FAPAR), the vegetation cover fraction (Fcover), and the albedo from data from several large field of view space sensors (Vegetation, AVHRR, POLDER and MERIS) over the 1997-2003 period.

The POSTEL Service Center generated and distributed 5 years (1999-2003) of LAI, FAPAR and Fcover (animation below) derived from Vegetation 1 & 2 data. These products are available for free to the scientific community on the POSTEL web site. The variables are evaluated by the version 3.1 of the algorithms of CYCLOPES project developed by CSE team of the INRA in Avignon, POSTEL Expert Center.

Animation parametre Fcover
Fcover parameter animation derived from Vegetation 1 & 2 data
(AVI format, ~19 Mb)

CYCLOPES LAI participates to a validation exercise of existing global LAI products, coordinated by GSFC/NASA in collaboration with POSTEL and other suppliers of the products. The process comprises:

  • an intercomparison with products developed within other projects (MODIS, GLOBCARBON, ECOCLIMAP, CCRS)
  • the comparison with ground measurements acquired on experimental sites of VALERI, BIGFOOT,..., networks spatialized with high resolution satellite images.

The first results were presented during the Global Land Vegetation Monitoring workshop which was held in Missoula (USA) from 8 to 10 August 2006, and the 2nd International Symposium on Recent Advances in quantitative Remote Sensing which was held in Valencia (Spain) from 25 to 29 September 2006. They show that CYCLOPES LAI has the best spatio-temporal consistancy, and are the best compared to the ground measurements, even with the low values over the more resistant vegetation. A publication is under writing.