I am trying to derive TOA radiance from Sentinel-2 L1C. To do so I am using the “Reflectance to Radiance” processor (under Optical->Preprocessing in SNAP). It seems to work okay and provides some output, but what are the units of the resulting dataset? It should be something like W m-2 sr-1 μm-1 but in Snap it is labeled as “dl”, i.e. dimensionless, and the values look somewhat unrealistic based on my experience so I want to make sure before continuing with the analysis. The units do not appear to be documented in the Snap help.
Are there any other scale factors or so to take into account when interpreting the results of the “Reflectance to Radiance” operator? Or is the output indeed given as W m-2 sr-1 μm-1? In the latter case it would be good if Snap showed this instead of “dl” (or at least mentioned the output units in the help under the algorithm description).