I would like to know which Sentinel-2 product is better T30TTK and T29TQE.
On Copernicus I can find two images with the same sensing date that differ only in the “Tile Number” field. They are projected differently onto the map and the values in bands are slightly different. In my image B1 reflectance is 0.1419 for TTK and 0.1464 for TQE.
Which one is closer to reality?
The question is off-topic for SNAP development and usage, but I will appreciate if you answer, as I didn’t find a specification of this.
I have loaded the KML file with Sentinel-2 tiles and seen that, indeed, over my region in Spain they overlap.
I can reformulate the question this way: is it just a processing issue, so overlapped tiles are processed automatically two times on T29 and T30 tile?
If you talk about Level2 then it can be because the AC is done per tile. It depends on the actual values in the scene (min, max, mean, or something like this). But they are equally good. For details, you should ask sen2cor.
If you talk about Level1 then I don’t know. Could be that the differences are caused by different processing versions even if the scene is taken from the same date?
Maybe @Jan has an answer?
Thank you, changed the category. Does AC stand atmospheric correction?
Yes. Sen2cor is the ESA standard tool to do the atmospheric correction on Sentinel-2 data.
Your L1C Tiles areTop-of-atmosphere (TOA) reflectances in cartographic geometry. The Tile Naming Convention for these two Tiles indicates one is from UTM Zone 29, and the other from UTM Zone 30. Looking at the position of the two Tiles in the Tiling Parameters file (TILPAR) available here: https://sentinel.esa.int/documents/247904/1955685/S2A_OPER_GIP_TILPAR_MPC__20151209T095117_V20150622T000000_21000101T000000_B00.kml they almost overlap entirely:
It’s not clear to me what the “typical” reflectance under this level of illumination should be - being as both are within the specification of radiometry for the the instrument, and that the value will be a within a range that will undoubtedly vary depending on viewing conditions.
You might find more information on the spectral response of S2A and S2B in the Sentinel-2 Spectral Response Functions document (https://sentinel.esa.int/documents/247904/685211/S2-SRF_COPE-GSEG-EOPG-TN-15-0007_3.0.xlsx).
As ever, the Level-2A, being the Bottom Of Atmosphere product (BOA) reflectance which will be a better representation of the surface values.
S2 MPC/CC Operations Manager