What command do I need to mask cloud shadow for S2 images during atmospheric correction - I assume cloud shadow isn't masked by default?
I tried to produce a mask for cloud shadow (l2_flags.LOWLW) but looks like cloud shadow isn't masked at all.
The LOWLW flag is a simple threshold on the retrieved water-leaving radiance in the green band closest to 555nm. The value of that threshold
is 0.15 uWatts/cm2/nm/sr - or one half the nominal open ocean clear sky value. While it is used to flag data as likely within a cloud shadow, it's
not perfect and it has not been evaluated for it's effectiveness with the MSI instrument.