How to get CDOM (Coloured Dissolved Organic Material) and DOC (Dissolved Organic Carbon)

snap
1

Hello; Does anyone knows how to get B3/B4 ratio in SNAP (as a graph or other…) to be able to get CDOM (Coloured Dissolved Organic Material) and DOC (Dissolved Organic Carbon) levels.

2

You can use the Band Maths. There is a video tutorial for it:
SNAP - Band Math - YouTube

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3

Thank you so much Marco

4

which band ratio should I use, @Marco_EOM? Is it possible to get after the C2RCC process?

5

I would suggest that you use the normalized water leaving reflectance (rhown).
The ratio would be rhown_B3/rhown_B4.

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6

Thanks! And for the DOC, which band ratio should I use? Are there any documents that actually describe the usefulness of the outputs after processing the C2RCC?

7

Sorry, I don’t really know. I’m also only googling. But in one of the very first results this equation is used.
DOC = exp(0.544×log(Rrs(B1))-0.571xlog(Rrs(B2))-2.181xlog(Rrs(B3))+1.398×log(Rrs(B4))-1.406)

It is this paper: Capturing dissolved organic carbon dynamics with Landsat-8 and Sentinel-2 in tidally influenced wetland–estuarine systems

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8

Thanks, Marco. Just one last question—does Rrs(B1) represent normalized water-leaving reflectance, top-of-atmosphere reflectance, or simply the spectral band as downloaded (resampled) from the Copernicus data browser?

9

I would use the rohwn too. It is the better reflectance.

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10

Thanks a lot!