Minimize Level 2 Processing Overview
The global SYN Level-2 algorithm is divided into two main parts:
  • SYN Level-2 processing aims to combine information from the OLCI and SLSTR instruments to provide improved data for land surface analysis and to output the SY_2_SYN package.
  • The second part, VGT-P processing, aims to output the SY_2_VGP and the SY_2_VGK. SY_2_VGP is designed to be Vegetation-like product to continue SPOT observation and SY_2_VGK is the input file for SYN software dedicated to the VGT-S products.

Note that, in the frame of coming evolutions, a specific global aerosol module will be added in the SYNERGY Level 2 processor. The level of inclusion is not yet specified (separate module or included in SYN Level 2). The main adaptations envisaged are known but details and equations are not yet defined:

  • Inversion procedure to retrieve continuous aerosol component mixture,
  • Inclusion of prior climatology of aerosol properties to constrain retrieval, especially SSA.
  • Uncertainty estimate per retrieval,
  •  Generation of new LUT set to include 4 aerosol components (dust, sea salt, fine mode strong absorbing, fine mode weak absorbing), and all combinations of 25% mixtures of these, at wavebands/geometries for both SLSTR and OLCI. 
  • Adaptation of CCI aerosol retrieval method both for SLSTR channels and solar/view geometry, and for SLSTR/OLCI synergy. Over glint-free ocean an adaption of spectral estimation will be investigated to allow retrieval with SLSTR nadir view only.
  • Cloud masking, this section is a specific task in the "New Products" contract. The results of several algorithms will be investigated (combination between pseudo-bayesian and OLCI approaches, idePix, Gomez Chova Approach …) and the best approach will be then implemented.
  • Inclusion of ocean model giving surface reflectance and uncertainty, dependent on wind speed, ocean colour, for SLSTR & OLCI wavebands and view geometry.