Output units of "Reflectance to Radiance" operator

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).

This was reported previously and will be available in next SNAP release.
The unit is Watts/m^2/micrometer/steradian.

You already have TOA radiances in L1C.

Thanks Oana, very helpful!

abruescas, L1C provides TOA reflectance, not TOA radiances.

Oh yes, you are right, more used to OLCI, sorry.

On a somewhat related note, the “ReflectanceToRadianceOp” that is listed in GPT and available in the regular Snap Menu does not seem to be available under the “Add -> Optical -> Pre-Processing” menu in Graph Builder in Snap. Is this a bug or intentional?

Reflectance to Radiance it’s intentionally disabled from GraphBuilder.