The harmonization takes advantage of the similarity in spectral bandpass placement, spatial resolution, and overpass time between Landsat-8/9 and Sentinel-2A/B. To make the data comparable as if they come from the same sensor, the harmonization applies to the data of all sensors: the same atmospheric correction code (LaSRC), the same cloud/shadow masking code (Fmask), a view angle effect correction with a BRDF model, the subtle adjustment of the Sentinel-2 bandpasses to the Landsat ones, and the gridding of the HLS surface reflectance and quality assessment data to a common spatial reference system.

Landsat 8 and 9, Sentinel2AB band comparison