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

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

Hi Jody,

Thanks for the reply. The tracer field look fine, I also checked the convection adjustment index and there are no irregularities found here.

Best regards,
Elian

Van: MITgcm-support <mitgcm-support-bounces at mitgcm.org> Namens Jody Klymak
Verzonden: donderdag 3 april 2025 20:41
Aan: mitgcm-support at mitgcm.org
Onderwerp: Re: [MITgcm-support] Irregular Velocity Fields Near Basin Boundaries in MITgcm

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Hi Elian,

I would look at your tracer fields.  Is that maybe just (poorly resolved) convection?

Cheers,   Jody

From: MITgcm-support <mitgcm-support-bounces at mitgcm.org<mailto:mitgcm-support-bounces at mitgcm.org>> on behalf of "Vanderborght, E.Y.P. (Elian)" <e.y.p.vanderborght at uu.nl<mailto:e.y.p.vanderborght at uu.nl>>
Reply-To: "mitgcm-support at mitgcm.org<mailto:mitgcm-support at mitgcm.org>" <MITgcm-support at mitgcm.org<mailto:MITgcm-support at mitgcm.org>>
Date: Thursday, April 3, 2025 at 8:25 AM
To: MITgcm Support <MITgcm-support at mitgcm.org<mailto:MITgcm-support at mitgcm.org>>
Subject: [MITgcm-support] Irregular Velocity Fields Near Basin Boundaries in MITgcm

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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

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