[MITgcm-support] Irregular Velocity Fields Near Basin Boundaries in MITgcm

[Vanderborght, E.Y.P. (Elian)]

Dear MITgcm community,
I am running MITgcm in a rectangular basin with a single-hemisphere setup. However, I am encountering irregularities in both vertical and horizontal velocity fields near the basin boundaries (see attached figure).
Initially, I suspected insufficient horizontal viscosity. While increasing it to unrealistically high values reduced the issue, it did not resolve it entirely. I have also tested the following:


  *   Decreasing time-step,
  *   Using different advection schemes,
  *   Increasing horizontal diffusion,
  *   Increasing vertical viscosity.


None of these approaches have fully addressed the problem. I have also reviewed studies using similar setups, but they do not report encountering this issue. Does anyone have insights into what might be causing this or suggestions for a fix? I have attached my data file and SIZE.h for reference.
Any help would be greatly appreciated.

Best regards,
Elian

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250403/cc4ba1e2/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data
Type: application/octet-stream
Size: 2123 bytes
Desc: data
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250403/cc4ba1e2/attachment-0001.obj>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: SIZE.h
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250403/cc4ba1e2/attachment-0001.h>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Velocity_fields_Run.png
Type: image/png
Size: 221852 bytes
Desc: Velocity_fields_Run.png
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250403/cc4ba1e2/attachment-0001.png>