Does anyone know the equation for converting Sentinel 2 level 1c products from reflectance to TOA radiance?
I've looked at the Sentinel user guides but can't find anything. I'd rather use ArcGIS than SNAP, if possible.
I've actually just found the equation on the ESA SNAP help section under 'reflectance to radiance algorithm specification'.
If anyone else needs it, I used the following:
radiance = ((pixelValueBandX * cos(incidenceAngle) * solarIrradianceBandX) / (pi * d2)) / 10000
where d2 is 1.0/U
values for incidenceAngle, solarIrradianceBandX and U can be found in the 2 metadata files included in the download.