The leaf area index (LAI) is defined as half the total foliage area per
unit of ground surface (Chen and Black, 1992).
The production of LAI relies on the outputs of the current
ESA / GLOBCARBON
and FP5 / CYCLOPES
projects, which are available, respectively, at
VITO and
MEDIAS-France. In the frame of geoland, an
inter-comparison of multi-sensor GLOBCARBON products and the CYCLOPES VEGETATION LAI products has been carried out by MEDIAS-France and Noveltis, based upon a physical approach which consists in checking the spatio-temporal consistency of at the continental scale and on a full vegetation cycle. The absolute validation is done
using reference maps derived from in-situ measurements acquired on the
VALERI network
sites. The results have been presented in the GLOBCARBON User Workshop in January 2006.
The CYCLOPES and GLOBCARBON LAI products are also involved in a large intercomparison exercice lead by GSFC/NASA. The results have been presented in the Global Land Vegetation Monitoring workshop in Missoula, August 2006. They are available in the POSTEL web site. A scientific paper is under preparation.
Global LAI at 0.5° resolution derived from
VEGETATION measurements for years 2002 and 2003
MEDIAS-France defines the customization specifications of the LAI to fit
the requirements of
ONC,
and OFM:
- ONC needs 0.5°x0.5° tiled averages (mean and standard deviation values)
maps of LAI for 8 vegetation classes ("conifer evergreen
forest", "deciduous forest", "broadleaf evergreen forest","grassland
C3","grassland C4", "crops C3", "crops C4"). The number of valid pixels
available to compute the average is also provided, because it is useful
to assess the product quality.
- OFM requires LAI from 1st April to 30th June
for each year,for validation process over Poland in order to
monitor the crop growth cycle.
This customisation has been applied to the version 1 of CYCLOPES LAI products. These customized products are available for download through the link below.
Today, the version 3 of CYCLOPES LAI products is available through the POSTEL web site with associated scientific and technical documentation.
References
Chen, J. M. and T. A. Black, Defining leaf area index for non-flat leaves,
Plant, Cell and Environment, 15, 421-429, 1992.
