Sharing pyGOTM: a Python/Numba GOTM reimplementation with FABM coupling

[alinbobolea]

Hello GOTM community,

I would like to share a project I have been working on called pyGOTM:

https://github.com/alinbobolea/pygotm

pyGOTM is an open-source Python/Numba reimplementation of the General Ocean Turbulence Model. The goal is not to replace GOTM or FABM, but to make GOTM-style one-dimensional ocean and lake turbulence modeling more accessible to scientists and engineers working in the Python ecosystem.

The project focuses on preserving the scientific structure of the original GOTM Fortran implementation, using Numba for compiled single-column performance, supporting YAML configuration, producing reproducible NetCDF/xarray outputs, validating against GOTM reference cases, and exploring FABM/pyfabm coupling from Python.

I wrote a longer technical note here:

https://alinbobolea.github.io/blog/pygotm-fortran-to-python/

I am sharing this because FABM is an important part of the aquatic modeling ecosystem, and I would appreciate feedback from experienced FABM users on the coupling approach, compatibility expectations, validation priorities, or anything that looks incorrect or incomplete.

My intent is to contribute something useful to open-source aquatic modeling, especially for education, experimentation, reproducible workflows, and future model-coupling work.

Thank you,
Nick

[hburchard]

Dear Nick,

I am very much impressed about the work that you did with GOTM. I read your blog entry, and see how much of a complex work you have been doing. And I agree with you, that for many young people some old fortran code feels like quite a steep learning curve.

It would be nice, if the GOTM developers could have an online meeting with you, discussing some of the background of your developments and the next steps ahead. In case you are interested, we could try to have a meeting in early July.

What do you think?

Best regards, Hans.

[alinbobolea]

Dear Hans,

Thank you very much for your kind words of encouragement and your appreciation of pyGOTM. I would be delighted to have the opportunity for a discussion with GOTM developers in early July. Please let me know if there are particular topics of interest you would like to touch upon.

Best regards,
Nick

[hburchard]

Dear Nick,

for me, July 10 would work well in the morning (9 am CEST). How does this work with the others? Karsten, Jorn, Knut, Lars?

As for the topics, I do not have any preference, but the others certainly might have and should write them down here.

In case that July 10 at 9:00am CEST would not work, I could open a doodle with more options.

Best regards, Hans.

[lumlauf]

Hi all - July 10 would also work for me. Great work, Nick! Looking forward to hear more about this.

…

-Lars

On 6/6/2026 10:24 AM, Hans Burchard wrote: Dear Nick, for me, July 10 would work well in the morning (9 am CEST). How does this work with the others? Karsten, Jorn, Knut, Lars? As for the topics, I do not have any preference, but the others certainly might have and should write them down here. In case that July 10 at 9:00am CEST would not work, I could open a doodle with more options. Best regards, Hans. — Reply to this email directly, view it on GitHub <#87?email_source=notifications&email_token=AEVOCRJEABNPJPZDJDD3RW346PIKRA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCNZSGAYDSNJYUZZGKYLTN5XKU43VMJZWG4TJMJSWJJLFOZSW45FMMZXW65DFOJPWG3DJMNVQ#discussioncomment-17200958>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEVOCRKA47FYAF3WBGLLNH346PIKRAVCNFSM6AAAAACZS2DME6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTOMRQGA4TKOA>. Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AEVOCRKAV3OXGVTK2UMHSZ346PIKRA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCNZSGAYDSNJYUZZGKYLTN5XKU43VMJZWG4TJMJSWJJLFOZSW45FKMZXW65DFOJPWS33T> and Android <https://github.com/notifications/mobile/android/AEVOCRJSKCQ4CWKQVU7HAPL46PIKRA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCNZSGAYDSNJYUZZGKYLTN5XKU43VMJZWG4TJMJSWJJLFOZSW45FOMZXW65DFOJPWC3TEOJXWSZA>. Download it today! You are receiving this because you are subscribed to this thread.Web Bug from https://github.com/notifications/beacon/AEVOCRMC7HS5LVSFAA7CSYD46PIKRBFCNFSM6AAAAACZS2DME6WGG33NNVSW45C7OR4XAZNRIRUXGY3VONZWS33OINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQBAZ3T5JTSMVQXG33OVJZXKYTTMNZGSYTFMQ.gifMessage ID: ***@***.***> [ { ***@***.***": "http://schema.org", ***@***.***": "EmailMessage", "potentialAction": { ***@***.***": "ViewAction", "target": "#87?email_source=notifications\u0026email_token=AEVOCRMZ7S65AJCGXSMZUIT46PIKRA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCNZSGAYDSNJYUZZGKYLTN5XKU43VMJZWG4TJMJSWJJLFOZSW45FLM5WWC2LML5RWY2LDNM#discussioncomment-17200958","url": "#87?email_source=notifications\u0026email_token=AEVOCRMZ7S65AJCGXSMZUIT46PIKRA5CNFSNUABIM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63SDN5WW2ZLOOQXTCNZSGAYDSNJYUZZGKYLTN5XKU43VMJZWG4TJMJSWJJLFOZSW45FLM5WWC2LML5RWY2LDNM#discussioncomment-17200958", "name": "View Discussion" }, "description": "View this Discussion on GitHub", "publisher": { ***@***.***": "Organization", "name": "GitHub", "url": "https://github.com" } } ]

-- ------------------------------------------------ Lars Umlauf Department of Physical Oceanography Leibniz-Institute for Baltic Sea Research phone : ++49 381 5197 223 fax : ++49 381 5197 114 web :www.iow.de/lars-umlauf-en.html address: Leibniz-Institute for Baltic Sea Research Seestrasse 15 D-18119 Rostock-Warnemuende Germany -------------------------------------------------