GEOV2-AVHRR: updated and consolidated plant data
CNES, in collaboration with THEIA Vegetation Biophysical Variables experts, has updated the GEOV2-AVHRR product, a unique time series documenting changes in global vegetation since 1981. This product provides data on three essential vegetation variables:
- Leaf area index (LAI): sum of the half-surface area of photo synthetically active plant organs.
- Fraction of photosynthetically active radiation absorbed (FAPAR).
- Vegetation cover fraction (FCOVER).
These variables are calculated using data from the AVHRR advanced radiometer, which has a spatial resolution of 4 km and covers 41 years of measurements.
The update for the period 2017-2022 responds to two major changes:
- Switch to METOP-B AVHRR data: Due to the orbital drift of NOAA-19, METOP-B AVHRR data have been used since 2017.
- Integration of the latest LTDR versions: LTDR v4 is applied to NOAA data (before 2017), and LTDR v5 to METOP-B data (since 2017).
This process required algorithmic developments by CSIC, adjustments to the processing chain, and rigorous scientific validation of the results.
The GEOV2-AVHRR products modified for the 2017-2022 period are now in version R02, while those for 1981-2016 remain in version R01. All the data can be accessed via the Postel THEIA website under the Etalab V2.0 licence. Here are the monthly LAI data for 2022.
The historical depth of the data also makes it possible to illustrate global photosynthetic dynamics since 1981. We couldn’t resist offering you an animation of monthly data over 41 years, from 1981 to 2022, with a resolution of 4 km². This global and historical perspective on changes in vegetation makes it possible to understand the major changes documented by the GEOV2-AVHRR product. You can also find out more about the product and its developments by consulting the full documentation on the THEIA website.
Coming soon via the GEODES portal
By early 2025, the GEOV2-AVHRR product will be migrated to the GEODES portal (geodes.cnes.fr), which will bring together all the products produced by CNES for THEIA outside hydrology. At that point, the Postel site will be closed for good.
