Are S2 Level 2A products pixel values reflectance?

[si.patsalidis]

Hey, im having trouble to understand the Level 2A products .

I downloaded those products, and i dont know whether the pixel values are reflectance values ! And if yes are TOA or BOA ? the pixel values as i checked goes like 900, 1000 and so (not between 0 and 1 like reflectance is), like they are multiplied with a coefficient or something !

L2A BOA reflectance are supposed to be generated from Level 1C (TOA reflectance) using the senntinel 2 toolbox.

But when i download the L2A, are TOA reflectance and if i want to convert it to BOA i use the toolbox ?

[ABraun]

@si.patsalidis

the pixel values as i checked goes like 900, 1000 and so (not between 0 and 1 like reflectance is), like they are multiplied with a coefficient or something !

exactly, this is given in the metadata by the QUANTIFICATION_VALUE.

QUANTIFICATION_VALUE of Sentinel-1C

Hello, Just for information; The QUANTIFICATION_VALUE parameter was changed from 1000 to 10000 at Processing Baseline 02.00 (30th November, 2015). All subsequent processing baseline increments (we are now on 02.04) use 10000. Cheers Jan S2 MPC Operations Manager

L2B BOA convert (dl) to Reflectance values)

Hi All, If you could help plz, ur time much appreciated @Gongrau @ph3758 @Igor am a bit confused so if any one could help me in this plz. To convert the dl of BOA L2B product to Reflectance values I shoul do the following: Raster > Band Math > then writting this equation ( For example for B4) : B4 / 1000 as below: [image] But when I am previewing the spectral view for the pixcels it shows me the dl values ? [image] any idea if I am doing the wrong method to obtain the reflectance …

You find many of the answers in the sen2cor manual:

S2-PDGS-MPC-L2A-SUM-V2.4.0.pdf

[si.patsalidis]

so, what are the level 2A products before processing them to BOA reflectance (as i download them) ? TOA reflectance with the quantification value?

[obarrilero]

Hi,

L1C products -> TOA reflectances
L2A products -> BOA reflectances

In both cases, the pixel stores an integer to save space in the disk. For converting these DNs to the reflectances, you have to apply the quantification value. When you open the product in SNAP, this quantification value is applied automatically, but when you open only a jp2 file, you have to apply this quantification value manually.