The Level-2 VGP SYN product (SY_2_VGP) is produced by the Global Synergy Level-1/2 software and contains 1 km VEGETATION-like product TOA reflectances.
The "1 km VEGETATION-like product" label means that measurements are provided on a regular latitude-longitude grid, with an equatorial sampling distance of approximately 1 km. This product is restricted in longitude, including only filled ones.
This product is referred to as SPOT Continuity Product, adapted for scientific applications requiring highly accurate physical measurements. As a consequence, data are corrected for systematic errors (such as error registration of the different channels or calibration of all the detectors along the line-array detectors for each spectral band) and resamples to predefined geographic projections.
The measurements files focus on four specific spectral bands.
- B0 channel, corresponding to blue spectral region with a central wavelength of 450 nm (computed using all OLCI bands between 420 and 500 nm).
- B2 channel, corresponding to red spectral region and with a central wavelength of 645 nm (computed using all OLCI and SLSTR bands between 600 and 770 nm).
- B3 channel, corresponding to NIR spectral region and with a central wavelength of 835 nm (computed using all OLCI and SLSTR bands between 730 and 965 nm).
- MIR channel, corresponding to SWIR spectral region and with a central wavelength of 1665 nm (computed using SLSTR bands between 1500 and 1750 nm).
The Spectral Response Function used to transform OCLI/SLSTR bands into VGT bands is the one associated with SPOT/VGT-1. An update to the SRF associated with PROBA-V is planned by the end of 2022.
Several additional pieces of information are contained in this product but provided on a sub-sampled grid (every 16th pixel).
- Status flags providing information about cloud, ice, snow or land presence and information about quality of spectral channel measurement.
- Geometric viewing conditions (view zenith and azimuth, sun zenith and azimuth).
- Aerosol optical thickness.
- Total column ozone.
- Total column water vapour.