Minimize Pre-Processing

Starting with Level-1B TOA radiances, this process derives reflectances corrected for gaseous absorption and smile effect. It also allows for consolidation of the pixel classifications from Level-1B. Water vapour retrieval is a by-product of gas correction.

This process is divided into five main steps:

  1. Extraction of data from the input Level-1B packaged product including quality checks, conversion from radiance to reflectance (of both measurements and error estimates) and interpolation tie-points data onto a pixel grid.
  2. Pixel classification.
  3. Correction of the TOA reflectance for the absorption by atmospheric gases, for clear sky pixels, including the retrieval of the integrated column water vapour.
  4. Smile correction: instrumental correction of TOA reflectance for in-FOV variation of the channel's central wavelength.
  5. Surface reclassification of clear-sky pixels where necessary.

Note that the order of the steps is important.