Obtaining Excel files of Lat-Lon-SLA L3 data as presented
#1
Hello,
I am a 77 year-old physical oceanographer interested by a dramatic low having been observed on the Polynesian Maupiti Island (16.4 °S-152.3 °W) exactly during the SWOT path of Dec. 30, 2023.
I fully rely on the SLA L3 data accuracy at the 250-m pixel level that, I believe, is demonstrated by permanent small scale structures such as the bean-shaped low in the west of the island displayed on the https://swot-calval.oceandatalab.com/ site. Unfortunately, these permanent small scale structures demonstrate that the considered geoid is not fine enough and I would like to perform averages of the SLA L3 data as they are computed and presented to try specifying them and inferring the oceanic signal (considered to be the small scale variable part and not considering the large scale part due to the tides and the atmospheric pressure) in a relatively small latitudinal interval (16.4 to 17.0 °S) where I expect eddies to have possibly occurred
Could it be possible to obtain Excel files of the SLA L3 pixels in the form Lat-Lon-SLA for a dozen descending paths, ideally without any error, in this latitudinal interval?
Since this would necessitate some extra work, I could specify the dates of these convenient paths and send a manuscript presenting the observations and what has already been done with SWOT data (those on Dec. 30, 2023 are the lowest ever observed) and nadir data (that indicate a 200 km eddy nearby) with the help of a colleague from LEGOS who has no more time to help me.
And we could exchange directly using our e-mails...
With my many and sincere thanks in advance.
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#2
Hi Claude,

Sorry for the late reply, there weren't many people available at ODL the last few weeks due to holidays and conferences.

I downloaded files with an even pass number (descending) from the SWOT L3 Unsmoothed (250m) product for Dec. 30, 2023 and extracted "ssha_filtered" values located in the [-17.0, -16.4] latitudinal band. The "ssha_filtered" variable is described as:
Height of the sea surface anomaly with all corrections applied and with calibration, data selection and noise reduction (using Unet model) applied

Saving these values in an Excel file was not convenient, so I stored them as CSV files (should be easy to import in Excel) named after the NetCDF file values are extracted from. As these files are quite big, they have been compressed in a zip archive available here: https://ftp.odl.bzh/odl/sherleda/maupiti...30_sla.zip

I repeated the same process for all descending passes nearby French Polynesia between Dec. 16, 2023 and Jan. 23, 2024 (thus covering two SWOT cycles: 008 and 009), the results are available in this zip archive: https://ftp.odl.bzh/odl/sherleda/maupiti...23_sla.zip

Please note that:
  • the pass over Maupiti on Dec. 30, 2023 (pass #444) is included in both zip archives
  • Longitude values are expressed in the [0, 360]° range (same as in the NetCDF files)

I hope I understood correctly what you wanted and that these files will be helpful.

Best regards,

Sylvain
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#3
Hi Sylvain,
Many sincere thanks for what you have done for me.
I am able to read data with the two links you provided but it is clear that I did not correctly explain which files I need so that I think it will be more efficient to better explain.
I am preparing a detailed reply I will be able to send in less than a couple of hours... just hopping you are not in summer holidays!
A am very happy,
Sincere thanks,
Claude
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#4
(10 hours ago)Claude Millot Wrote: Hi Sylvain,
Many sincere thanks for what you have done for me.
I am able to read data with the two links you provided but it is clear that I did not correctly explain which files I need so that I think it will be more efficient to better explain.
I am preparing a detailed reply I will be able to send in less than a couple of hours... just hopping you are not in summer holidays!
A am very happy,
Sincere thanks,
Claude
Hi Sylvain,
Hoping you are still "in operation", please consider the attach doc and let me know.
With my very kind regards,
Claude
Reply
#5
Hi Claude,
Unfortunately I cannot see any document attached to your message.

In order to attach a file you need to first click on the "Browse" button under the "Attachments" section to select the file you want to send:


.png   2025-06-30-09:10:27_412x116_scrot.png (Size: 12.2 KB / Downloads: 3)

And then click on the "Add Attachment" button located on the right side of the same section:


.png   2025-06-30-09:10:56_469x105_scrot.png (Size: 2.54 KB / Downloads: 2)

Please note that there is a limit to 10MB for .doc and .docx files.

If it still doesn't work, feel free to send me the file by email (I sent you a message on Friday so you should have my address, maybe it ended up in the spam folder, let me know if you did not receive it).

Best regards,

Sylvain
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