Retriving chlorophyll and turbidity from sentinel data

Of course not. I’ll try to answer as good as I can.

As mentioned I am trying to estimate Chlr and TSM for different river reaches in Canada. Looking at the C2RCC parameters windows I guess i need to adjust some of the parameters. Do you know of any application of this processor for fresh water I could refer?

2 posts were split to a new topic: S2 MCI Processor does not generate results

Depending on the expected concentration of CHL and TSM you should select the proper neural net. The default net for concentrations up to ~20 and if the values get higher than use the C2X NNs. You can also set the salinity to a small value (not zero), but this has no high impact on the results.
That’s it already.

Hello Forum

I created several C2RCC analyses from a temporal series of S2; I would like now to export the results to a grid so I can use it in ArcGIS. Following some guidelines I subset the processed file only to include one band (Chlr) and then export it as Geotiff. Am I correct?

thanks in advance

Giancarlo

Please take a look at the end of this post,

Source of the post

Super thanks!!!

Just an add-on, if the the band extractor does not appear in your menu ( Optiacal) go in Tools and select plug-ins

Thanks as usual for the great feedback!

Giancarlo

In my case it’s available, but check up the SNAP update. I thin band extractor already comes within SMAP.

Hello Forum

I run the Chlr processor using the C2X-Nets. As I run of a river I set the salinity to 0.1 and the temp to 25C
All the rest of the parameters are default with the exception of the “No uncertainties”; the processor
works well to separate the water body but the detected chlr, is way lower than a local sampling done (at lease 1 magnitude of volume). Any suggestion?

Thanks

GIancarlo

Dear sir thank you for your all Kind reply, But since I have not clear with how the C2RCC processer work if u don’t mind can u simplify me?

Thank You

Can you please specify your question? The general framework of the processor is described in the Help section of SNAP

You input Sentinel-2 (L1C) products and adjust the parameters in the second tab and then run it.
The chlorophyll and suspended matter concentrations are then stored in the conc folder:

grafik

In S2 C2RCC is common for all case 2 water for retrive chlorophyll or it may vary based on the region?

as long as you adjust the temperature and salinity value of the water and maybe some atmospheric parameters, you can apply it to different regions.

The quality can be different for different regions. You should have insitu data to compare the results with real data.
As @ABraun said, you.can provide salinity and temperature to improve the results.
Also the factors and exponen for tsm and chl computation can be adapted to match your region.
image
You have to find out which values are best.
When opening the properties for the band you can edit the values.
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Once you found good values you can provide them to the processing.

You can find the equations in the properties
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image

conc\_chl = iop\_apig^{1.04} \times 21.0

What C2RCC compuites is actually chlorophyll_a, so yes you can compare them.

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Hello mr.
I do not want to use Snap processors to estimate chlorophyll-a.
I would like to estimate chlorophyll-A in MATLAB software.
Does for input the Sentinel-2 L1C (TOA) data in MATLAB software require the atmospheric correction of Sentinel-2 L1C (TOA)?:thinking:
Thank you Mr.

Yes, this would improve the accuracy of your results. There are some where the AC in negligible, but most computations benefit from an atmospheric correction. You could use the Sentinel-2 L2A data.

I have the Sentinel-2L1C image of April 4, 2019 from my case study.
But, the Sentinel-2L2A image of April 4, 2019 is not available in the database of the ESA (https://scihub.copernicus.eu/). please guide me.

If it is not available, you would need an atmospheric correction software. The common choice would be Sen2Cor plugin to SNAP (also possible to use stand-alone on command line). This should create the same product you would download from SciHub. Download here
https://step.esa.int/main/third-party-plugins-2/sen2cor/
and make sure you read the documentation. In case you run into problems, search this forum for Sen2Cor, because here is wast number of problem solving discussions - narrow the search also to version you use.
There are also alternative ways to do atmospheric correction, and the second obvious choice to try is iCOR-sentinel2-sta if you use SNAP, as it is available through “Tools/Manage external tools” menu in SNAP. I did not try iCOR yet, Sen2Cor works, but may not be that obvious to operate properly at first.