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ICDC
CENIntegrated Climate Data Center ICDC

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Vegetation Cover Fraction from SPOT/PROBA-V/S3-OLCI

Global vegetation cover
Aggregated COPERNICUS global land service vegetation cover fraction Aug 2015. Copyright: UHH/CEN/S. Kern

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Access

RESTRICTED: This link to the data set is only available for a restricted user group.  The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account.  Please contact ICDC if you would like to access this data from outside the network.

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Description

The Fraction of green Vegetation Cover (FCOVER) corresponds to the fraction of ground covered by green vegetation. Practically, it quantifies the spatial extent of the vegetation. It is independent from the illumination direction and it is sensitive to the vegetation amount. FCOVER is derived from the Leaf Area Index (LAI) and a number of structural parameters of the canopy. Used are top-of-canopy directionally normalized reflectances from SPOT-4 and -5, PROBA-V, and - more recently - Sentinel-3 OLCI in various spectral bands (12 for Sentinel-3 OLCI, 3 otherwise). These are used in a neural network approach which is trained with the best estimate of FCOVER from MODIS and CYCLOPES. Calibration of the neural network used for Sentinel-3 OLCI data is done with PROBA-V results.

For more information we refer to the ATBDs mentioned in the references section.

We offer various versions of this data set provided by COPERNICUS Global Land Service, see references.

Data were downloaded in netCDF file format with 1/112° (about 1km) grid resolution (SPOT / PROBA-V) and 1/336° (about 1/3 km) grid resolution (PROBA-V / Sentinel-3 OLCI) at global coverage. This data are available from ICDC. We offer in addition a block-averaged version of the SPOT/PROBA-V 1/112° data and the PROVA-V/S3-OLCI 1/336° data at a 0.5° x 0.5° plate carree grid. Data are available for the latitude range 60°S to 80°N (60°S to 75°N for PROBA-V / Sentinel-3 OLCI). Note, however, that limited solar illumination reduces the maximum northern latitude to smaller values during winter.

Last update of data set at ICDC: March 21 2024.

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Parameters

Parameters of the vegetation cover data set
NameUnit/RangeComment0.5°1/112°1/336°
Percent fraction of green vegetation cover 0 ... 100 % resolution is 0.25% x x x
Root-Mean squared error (RMSE) 0 ... 100 % resolution is 0.25% x x x
Number of land pixels 0 ... 3136 ... 28224 per 0.5° grid cell (see information in netCDF file) x    
Number of valid data pixels 0 ... 3136 ... 28224 per 0.5° grid cell / per 1/112° pixel or /per 1/336° pixel (see information in netCDF file) x x x
Mean number of usable satellite data 0 ... 120 per 0.5° grid cell x    
Cumulative number of usable satellite data 0 ... 188160 ... 1693440 per 0.5° grid cell x    
Number of days included before product date 0 ... 60 days     x x
Number of days included after product date 0 ... 60 days     x x
Bitwise quality flag 0 ... 255     x x
Surface type flag 1, 10, 20, 40

Dominant (major) surface type: See respective information about flag values and their meanings in the netCDF file

x

    
(Primary) retrieval flag 0 ... 24 (... 114)

Dominant (major) retrieval type: See respective information about flag values and their meanings in the netCDF file

x

    
Secondary retrieval flag (PROBA-V / S3-OLCI) 0 ... 114

Second most retrieval type: See respective information about flag values and their meanings in the netCDF file

x

    

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Coverage, spatial and temporal resolution

Period and temporal resolution:

  • 1998-11-10 to 2020-04-30 (SPOT/PROBA-V) 2014-01-10 to 2023-12-31 (PROBA-V/S3-OLCI)
  • 10-daily sampling, 60-day effective resolution

Coverage and spatial resolution:

  • Global
  • Spatial resolution: 0.5° x 0.5° and 1/112° x 1/112° (SPOT/PROBA-V), 0.5° x 0.5° and 1/336° x 1/336° (PROBA-V/S3-OLCI)
  • Geographic latitude: 90°S to 90°N and 60°S to 80°N (75°N)
  • Geographic longitude: 180°W to 180°E
  • Dimension: 360 rows x 720 columns and 15680 rows x 40320 columns (47040 rows x 120960 columns)
  • Altitude: follows topography

Format:

  • NetCDF

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Data quality

The data sets at 1/112° and 1/336° grid resolution contain a bit-wise to read quality flag. The content of the flag can be read at the COPERNICUS Global Land Service, Vegetation Cover Website under the tab "Technical" (see references).

The 0.5° x 0.5° data set offered in addition contains two basic separate flags. One flag refers to the two surface types where FCOVER retrieval is either impossible or prone to larger uncertainties. The other flag refers to the type of retrieval, i.e. whether data are interpolated or whether special corrections were applied to account for high latitude / high solar zenith angle illumination conditions. In addition, only the valid 1/112° x 1/112° or 1/336° x 1/336° grid points are used to compute the average value of the FCOVER and its uncertainty. As can be seen in the parameters section we give number of land pixels, number of valid pixels, and number of usable satellite data to convey information about reliability. We recommend to read the text given in the netCDF files.

FCOVER products have been validated and are reported to have a good quality, showing a spatial consistent global distribution of retrievals. Temporal profiles are very smooth and are highly consistent from year to year. Comparison with ground data shows that target accuracy is achieved, and no bias was detected. This applies to FCOVER based on SPOT-4 and -5 as well as on PROBA-V. More information about the validation efforts can be found in the validation reports listed under references.

We note that the PROBA-V/S3-OLCI data set contains jumps in the values when switching from combined PROBA-V/S3-OLCI to pure S3-OLCI between June 2020 and July 2020.

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Contact

Frederic Baret
Institut National de la Recherche Agronomique (INRA), France
email: frederic.baret (at) avignon.inra.fr

Bruno Smets
VITO, Belgium
email: Bruno.Smets (at) vito.be

Stefan Kern
University of Hamburg
email: stefan.kern (at) uni-hamburg.de

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References

Literature:

Websites:

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Data citation

Please cite the data as follows:

Baret, F., et al. (2013). GEOV1: LAI and FAPAR essential climate variables and FCOVER global time series capitalizing over existing products. Part1: Principles of development and production. Remote Sensing of Environment, 137: 299-309

Camacho, F., et al. (2013). GEOV1: LAI, FAPAR Essential Climate Variables and FCOVER global time series capitalizing over existing products. Part 2: Validation and intercomparison with reference products. Remote Sensing of Environment 137: 310-329

SPOT/PROBA-V: The product was generated by the land service of Copernicus, the Earth Observation programme of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programmes. The product is based on SPOT/VGT 1km data ((c) CNES / PROBA-V 1km data ((c) ESA and distributed by VITO) [when using the coarse-resolution data: provided on 0.5 degree x 0.5 degree plate carree grid] [last access date: August 26, 2020] in netCDF file format by the Integrated Climate Data Center (ICDC) University of Hamburg, Hamburg, Germany.

PROBA-V/S3-OLCI: The product was generated by the global component of the Land Service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V and Sentinel-3 data (© ESA)  [when using the coarse-resolution data: provided on 0.5 degree x 0.5 degree plate carree grid] [last access: March 15 2024] in netCDF file format by the Integrated Climate Data Center (ICDC) University of Hamburg, Hamburg, Germany.

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