In OLCI data it can happen that pixels are saturated, but they are not marked as such.
It is possible to identify and mask them.
Expression 1 computes the maximum gradient within the spectrum for each pixel
Expression 2 computes the band at which the maximum gradient occurs.
The second problem is that altitude pixel can be outside of the possible value range, e.g. *. +29153m or -10358m. In combination with a land mask such pixels could be masked.
Alternatively, wrong altitude pixels could be retrieved from a DEM (user option?).