Two different dates in Sentinel 2 dataset descriptions

[a.woerner (Andreas Wörner)]

Hello

I just started using Sentinel 2 data for exploring changes in tree vitality for certain areas in Germany.
Using Copernicus Browser to search for images I realized that, especially for newer images, two different datasets per image are offered e.g.:

S2A_MSIL1C_20210910T101031_N0500_R022_T33UUU_20230116T100413.SAFE
S2A_MSIL1C_20210910T101031_N0301_R022_T33UUU_20210910T122319.SAFE

When I calculate NDVI for the images I get quite different results, about 0.2 to 0.25 units lower when I use the first dataset.

Can someone tell me for what the second date and the changing N… values in the naming of the datasets stand for?
I guess it has something to do with the preprocessing of the images.
Another question would then be what do I have to take into account when comparing images from 2017 with images from 2021 and 2023 or rather where can I get further information about that?

Thanks for you help in advance.

Best
Andreas

[william.ray]

Hi Andreas,

This forum is a space specifically for Sentinel Hub services. For Copernicus Data Space Ecosystem questions, please use their Community Forum to ask your questions.

This is so that fellow Copernicus Data Space Ecosystem users will also see the answers you are seeking over in that community forum. Apologies for the confusion!