Some vegetation area appear red on the Natural Colours image

Optical Toolbox
#1

Hello,
I am new to image interpretation and processing with SNAP so my question may be basic but I didn’t find the answer in existing topics.
I opened a Sentinel-2 product in SNAP, then calculated the RVB image using the default Natural Colours profile (using Bands 4, 3 and 2 for Red, Green and Blue) and I got the following result. My question is : why are there red-coloured areas on the land ? These areas seem to be vegetation but what do they represent differently than other vegetation areas nearby ?

Le_Havre_estuaire_de_la_Seine_S2B_MSIL2A_20220227T105859_N0400_R094_T30UYV_20220227T133334_RGB_edited
Le_Havre_estuaire_de_la_Seine_S2B_MSIL2A_20220227T105859_N0400_R094_T30UYV_20220227T133334_RGB_edited1920×640 287 KB

(Location : Seine estuary, France)
Thank you for reading

#2

If you need some remote sensing basis, there are lots of materias on line:

https://www.nrcan.gc.ca/maps-tools-and-publications/satellite-imagery-and-air-photos/tutorial-fundamentals-remote-sensing/introduction/9363

And some course that you could apply for.

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#3

When in doubt you can always compare your own output with that at the EO Browser:

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#4

Hi @vuduciel Maxime,
this scene was probably acquired in winter, and what you circled are broadleaf forests withouts leaves, which are grey / brown in natural colours. Depending on the adaptation you used to have this nice blue colour on the sea, you might have given this reddish colour to these forests. Just before spring, the buds (bourgeons) can also give a reddish tint naturally.
Olivier

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#5

Thank you @OHagolle four your clear answer !