I noticed that Sen2Cor processing compared to level 2A on the copernicus website has different results to “scene classification” produtct. I am using Sen2Cor version 2.8.0 and if I compare the products of both, they are different:
I think this is the same reason as discussed here: Different colors in L2A images and here SNAP Tutorial
sen2cor outputs can only be compared with the preprocessed L2A products when the the same DEM is used and the ESA-CCI data package is included for sen2cor.
No, I think the DEM is the minor reason, but rather the CCI Landcover product which is additonally integrated. Again, please read the commend of Jan here: SNAP Tutorial
I wouldn’t trust any of them, to be honest, as they are automatically derived from every image based on robust routines. But they do not replace an adjusted classification. And the cloud masks are rather an indication for image quality, but also not ultimately correct.