Hello
I am a researcher who want to use SWOT_SIMULATED_L2_KARIN_SSH_ECCO_LLC4320_SCIENCE_V1 data. However, I find the ssha( I choose the ssha_karin) is very different from the eta of original LLC4320. And I find the ssha(ssha_karin) and ssh(ssh_karin) is the same. I am curious about that question, so i write this letter. Can you explain the reasons? The attached pictures are the same day that I drew using llc4320 and swot simulation. Thanks in advance.
swot simulator data questions
swot simulator data questions
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PODAAC - celiaoued
- Subject Matter Expert
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- Joined: Fri May 28, 2021 1:30 pm America/New_York
Re: swot simulator data questions
Hello,
My guess is that there is significant cross-swath bias in the simulated dataset. Perhaps this code from the community repository would help (https://github.com/SWOT-community/SWOT-OpenToolkit/blob/main/examples/remove_crossswath_bias.ipynb) If this is the case, then the difference between ssha_karin and ssh_karin should become clearer after cross-swath bias is removed.
Regarding eta versus ssha, I would check the documentation of SWOT (User Handbook and PDD: https://podaac.jpl.nasa.gov/SWOT?tab=datasets-information§ions=about) and any MITgcm documentation about the definitions of ssha and eta, respectively, and compare them.
Hope this helps!
My guess is that there is significant cross-swath bias in the simulated dataset. Perhaps this code from the community repository would help (https://github.com/SWOT-community/SWOT-OpenToolkit/blob/main/examples/remove_crossswath_bias.ipynb) If this is the case, then the difference between ssha_karin and ssh_karin should become clearer after cross-swath bias is removed.
Regarding eta versus ssha, I would check the documentation of SWOT (User Handbook and PDD: https://podaac.jpl.nasa.gov/SWOT?tab=datasets-information§ions=about) and any MITgcm documentation about the definitions of ssha and eta, respectively, and compare them.
Hope this helps!
Re: swot simulator data questions
Hello,
thank you for your suggestions, I follow your advise to deal with ssh and ssha with the code(https://github.com/SWOT-community/SWOT-OpenToolkit/blob/main/examples/remove_crossswath_bias.ipynb). However, there are still some problems about the ssh and ssha. The appendices contain the sea surface height (SSH) and sea surface height anomaly (SSHA) piture after I removed the cross-swath bias. However, there are still significant differences between them and the Eta values of LLC4320. I have also attached my code. If there are any errors or areas for improvement, I would greatly appreciate it if you could point them out. Thank you in advance.
thank you for your suggestions, I follow your advise to deal with ssh and ssha with the code(https://github.com/SWOT-community/SWOT-OpenToolkit/blob/main/examples/remove_crossswath_bias.ipynb). However, there are still some problems about the ssh and ssha. The appendices contain the sea surface height (SSH) and sea surface height anomaly (SSHA) piture after I removed the cross-swath bias. However, there are still significant differences between them and the Eta values of LLC4320. I have also attached my code. If there are any errors or areas for improvement, I would greatly appreciate it if you could point them out. Thank you in advance.
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- code.pdf
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PODAAC - celiaoued
- Subject Matter Expert
- Posts: 46
- Joined: Fri May 28, 2021 1:30 pm America/New_York
Re: swot simulator data questions
Hello,
Sorry to say I'm not able to help any further with science, as I mainly deal with matters of data access and documentation. Perhaps you could ask the ECCO folks https://ecco-group.org/home.htm , or any MITgcm experts, and compare the definitions and reference levels with that of the SWOT SSH products. Is it also worth considering - given that you are comparing 2 snapshots from LLC4320 and SWOT-simulated LLC4320, are they even comparable in absolute values, variance, or area-wide trend? Does the time difference between the simulated ascending passes and descending passes matter, and what is the time range covered by the simulated passes you are looking at?
Sorry to say I'm not able to help any further with science, as I mainly deal with matters of data access and documentation. Perhaps you could ask the ECCO folks https://ecco-group.org/home.htm , or any MITgcm experts, and compare the definitions and reference levels with that of the SWOT SSH products. Is it also worth considering - given that you are comparing 2 snapshots from LLC4320 and SWOT-simulated LLC4320, are they even comparable in absolute values, variance, or area-wide trend? Does the time difference between the simulated ascending passes and descending passes matter, and what is the time range covered by the simulated passes you are looking at?