The solar and view angles for the same ground target change with date and vary between the sensors, and this causes slight discrepancy in measurement. Normalizing the angle effect is desirable for a harmonized dataset. We selected the c-factor technique and the global coefficients provided by Roy et al. (2016).

The S30 and L30 reflectance products are normalized for per-pixel view and per-granule illumination angles. This applies to all S30 and L30 optical bands except the MSI red-edge bands and the atmospheric bands (Coastal aerosol, Cirrus, Water vapor) for which no BRDF information are available and no correction can be made with this technique. View angle is set to nadir and solar zenith is set to a temporally constant value at each tile’s center and varies with latitude given in the figure below.

Figure: Sun zenith Angle (SZA) and central latitude of all the scenes of the Landsat-8 archive. The line corresponds to the overall fit using a 6th degree polynomial, similarly as Zhang et al. (2016)