The SYN operational processor is divided into two components:
Global SYN Level 1/2 software deals with OLCI and SLSTR Level-1B products and gathers Level-1 processing and Level-2 processing.
The Level-1 processing computes OLCI and SLSTR radiometric measurements and associated annotation data in their acquisition geometry. The correspondence grids between OLCI reference pixels and all other OLCI and SLSTR pixels are also computed. Additionally, all parameters are projected on the same OLCI reference acquisition grid.
The Level-2 and VGT-P processing deals with this set of parameters (OLCI/SLSTR measurement and annotation data) projected on the same grid, to compute the Level-2 SYN product, Level-2 VGP product and Level-2 VGK products.
A dedicated VGT-S software deals with the VGK product to compute daily and decade synthesis of surface reflectance, based on the maximum value of NDVI (this composite method will be evaluated and updated in the frame of coming evolutions). It produces VG1 and V10 products.
Note that, in future evolutions, a global aerosol over Ocean and Land pixels, will be included in SYN global processing in order to provide near real-time data suitable for assimilation within numerical weather prediction models, and with potential to provide timely warnings related to air quality and visibility. This modification will imply updates in Level 1 processing (to include Ocean pixels) and in Level 2 processing.