Retriving chlorophyll and turbidity from sentinel data

Optical Toolbox
#21

Hi,
I am using S2A_MSIL2A product, resampled and subset. Then apply the following Optical \ Thematic Water Processing \ C2RCC Processor\ S2-MSI, but receive an error:
An internal error occurred during the target product initialization
Type: Illegal Agrument Exception
Message: [source] is null

What does the error mean? Is this product MSIL2A compatible with the C2RCC processor?

#22

Hello
For C2RCC you should use the L1C products. C2RCC is doing its own AC.

Regarding the error. It seems the source product is not correctly specified.
It would be good if you post the log file, if you still experience the error.
You can find it by selecting from the menu Help / Show Log Directory. Make sure to reproduce the error first and then attach the messages.log file.

1 Like
#23

OOOOOOOO, thank you !
That was really helpfull!

#25

Hello
I want to estimate the amount of chlorophyll (phytoplankton) in the study area. Do I use the WFR or ŁEFR sentinel-3?

#26

You have to start from Level 1B. So either EFR or ERR products.
In the Level 2 WFR products the chlorophyl is already contained.

1 Like
#27

Thank you sir.
I want to evaluate the amount of chlorophyll a by using Sentinel 2 data for my study area. To assess the results obtained from Sentinel 2 data, I do not have data extracted from the area. Can I use Sentinel 3 WFR or EFR data to evaluate Sentinel 2 results?

#28

I would not suggest it. You should have in-situ data to validate the results.
Comparing the results with the results from pther sensors would only be kind of plauibility check.
And you should not compare C2RCC of Sentinel-2 (S2) with C2RCC of Sentinel-3 (S3). The same approach is used for both and therefor will include the same errors, if any.
In addition the resultion if very different between S2 and S3. Maybe you can find or compute CHL and TSM values from Landsat. But again, better not comparing only with C2RCC results.
You can do a broader comparison. Using multiple sensors and multple algorithms. But at the end you might not know which restul to trust. So having real in-situ data is important.

2 Likes
#29

Thank you sir.
Im Sorry
Does the C2RCC window need insitu data in order to obtain chlorophyll A from the C2RCC algorithm in the Snap software?

#30

No, it only needs the satellite data. But if you want to validate the results you should have in-situ data.

1 Like
#31

thanks a lot.

#33

Hello, Mr Peters
I have 2 ask to you please answer to my questions

1- do for estimate the phytoplankton we must only use Sentinel-2A Level1-C or we can also use Sentinel-2B Level1-C?

2- What hour sentinel-2 will take photograph from Persian Gulf region (minab city)?
Please define to Greenwich time.

Thank you for your partnership.

#34

  1. You can use both, S2A and S2B.

  2. You can easily find out your self. Go to SciHub and define a region over manib city. Then do a search for S2 L1C. The you can see all the products and the sensing time.
    Beside this way, you can also use dedicated software like ESOV or SAMI

However, it seems that this area is passed at around 7:00

#35

thanks a lot.

#36

Hello, Mr Peters
I want video to calculate chlorophyll content with Sentinel 2 data.
Is there such a video?

Thank you.

#37

There is one Video for the Red-Edge-Position.
Go to the Tutorial section, select Sentinel-2 Toolbox category and there you find ā€œS2REP index usageā€.

You can also use the C2RCC for Sentinel-2 this is usable only for Water.
There is no video. But you can resample the S2 data to a common resolution and then open the C2RCC processor from the Menu: Optical / Thematic Water Procesing / C2RCC Processors/ S2-MSI

#38

thanks a lot.

#39

is the C2RCC processor also applicable to freshwater lakes?

I have the salinity in Ī¼S/cm from here:
https://riverdata.mdba.gov.au/lake-victoria

But I donā€™t know how to convert it into the PSU required by the tool.

Edit: I found an exel template to do it. http://www.schulbiologiezentrum.info/EXCEL-Programme/Leitfļæ½higkeit-%20und%20Salzgehalt-Rechner.xlsx
For 150 Ī¼S/cm and 22.7Ā° C it gives me 0.08 PSU. I donā€™t have an idea if this is feasible.

1 Like
#40

Hello Marco et al.

thanks for the valuable information.

I would like to use the C2RCC to estimate the Chlr in a specific river for which I have a series of S2 images available.
The S2 scenes takes sometime to process and I was wondering if by sub setting the image using the Snap tools I can still have valid results.

Any hints?

Thanks in advance

Giancarlo

#41

Yes, you can subset as you like. The C2RCC operates on single pixels. You can also use the value pixel expression to further limited the number of pixels processed. Also you should only compute the output you need, e.g. no uncertainties.

2 Likes
#42

I found this site now could calculate the salinity directly,

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