The physical content of the SY_2_AOD product is composed by the following files:

• Manifest file compliant with the SAFE format specification (XFDU)
  • "xfdumanifest.xml" – The manifest that explains at high level the contents of the package
• Measurement data files:
  • "NTC_AOD.nc" gathering all the derived and retrieved aerosol parameters at super-pixel resolution. Associated flags, uncertainty and contextual parameters for each super-pixel are also included in this file.

The structure of the manifest file is common to all products. More information can be found in the SENTINEL-SAFE description

The SYN Global Aerosol (AOD) processors only contain a measurement dataset providing all derived and retrieved aerosol parameters at super-pixel resolution. Contextual parameters such as time, quality flags, and geographical position are also included for each super-pixel.

Retrieved and derived aerosol parameters:

• AOD at 440, 550, 670, 985, 1600 and 2250 nm,
• Error estimates (1 s.d.) in AOD at 440, 550, 670, 985, 1600 and 2250 nm,
• SSA at 440, 550, 670, 985, 1600 and 2250 nm,
• Fine-mode aerosol optical depth at 550nm,
• Aerosol Angstrom parameter between 550 and 865nm,
• Dust aerosol optical depth at 550nm,
• Aerosol absorption optical depth at 550nm.

Products at L2 super-pixels for user interpretation:

• Latitude at super-pixel centre,
• Longitude at super-pixel centre,
• Pixel corner latitude 1..4,
• Pixel corner longitude 1..4,
• Sun zenith angle of nadir centre super-pixel,
• Satellite zenith angle of nadir centre super-pixel,
• Relative azimuth angle of nadir centre super-pixel,
• Acquisition time of nadir centre pixel,
• Cloud fraction within nadir super-pixel,
• Cloud fraction within oblique super-pixel,
• Quality flags to indicate high uncertainty in retrieval of AOD used, e.g. due to glint contamination. Flags give information on:

- Land / ocean retrieval algorithm

- Dual view / single view retrieval

- Glint risk in nadir

- Glint risk in oblique

- Surface reflectance retrieved negative

- Aod zero (<1e4)

- Fine mode fraction retrieval failed (fraction from climatology)

- Uncertainty estimation failed

- Retrieval rejected by the post processing

- Low NDVI case of land retrieval

Surface Product for diagnostics:

• Atmospherically corrected nadir surface directional reflectances at 440, 550, 670, 985, 1600 and 2250 nm at super pixel (4.5km) resolution.

Product Size

In the following table the approximate size of each SYNERGY file contained within the Level 2 Global aerosol product over one full orbit is given. The size computation assumes 60,000 lines of 300m per orbit for the purpose of size estimates, leading to nearly 8889 records of super pixel per orbit.