[MITgcm-support] MITgcm-support Digest, Vol 204, Issue 5

Fri Jun 12 13:36:47 EDT 2020

    Hi Igor,

it is perfectly possible to compute a reference state to compute available potential energy despite the nonlinear equation of state, as explained in the following paper (Saenz et al. 2015, JPO)

https://doi.org/10.1175/JPO-D-14-0105.1

Now, it is also possible to show that the 'true' available potential energy can be usefully approximately by taking the horizontally-averaged density field as an approximation to the true reference state as explained in Tailleux (JFM, 2013).

https://doi.org/10.1017/jfm.2013.509

Computing a good approximation of available potential energy for the ocean is much easier than most people imagine. The idea that it is (nearly) impossible to compute a meaningful APE budget for the ocean has been greatly exaggerated.

Good luck,
Remi.

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Today's Topics:

   1. Potential energy in MITgcm (Shevchenko, Igor)
   2. Re: Potential energy in MITgcm (Martin Losch)
   3. Re: Potential energy in MITgcm (Shevchenko, Igor)

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Message: 1
Date: Fri, 12 Jun 2020 09:23:02 +0000
From: "Shevchenko, Igor" <i.shevchenko at imperial.ac.uk>
To: mitgcm-support <mitgcm-support at mitgcm.org>
Subject: [MITgcm-support] Potential energy in MITgcm
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        <DB7PR06MB440935B3EC2B8F8766DEB425AA810 at DB7PR06MB4409.eurprd06.prod.outlook.com>

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Dear MITgcm users,

Is there a chance to diagnose potential energy in MITgcm?

Best regards,
Igor

------------------------------

Message: 2
Date: Fri, 12 Jun 2020 11:30:59 +0200
From: Martin Losch <Martin.Losch at awi.de>
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] Potential energy in MITgcm
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Hi Igor,

rhethorical question: what is potential energy in a GCM?

This is a bit complicated. You could just intergrate density vertically (and density or density anomaly can be saved via the diagnostics pkg), but you really only want to have available potential density, for which you need a reference state that is difficult (impossible?) to define for general case. So it?s always set-up specific.

Details of the actual computation also depend on details of your configuration (free surface linear/non-linear/r-star, etc.)

M.

> On 12. Jun 2020, at 11:23, Shevchenko, Igor <i.shevchenko at imperial.ac.uk> wrote:
>
> Dear MITgcm users,
>
> Is there a chance to diagnose potential energy in MITgcm?
>
> Best regards,
> Igor
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support

------------------------------

Message: 3
Date: Fri, 12 Jun 2020 09:55:55 +0000
From: "Shevchenko, Igor" <i.shevchenko at imperial.ac.uk>
To: "mitgcm-support at mitgcm.org" <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] Potential energy in MITgcm
Message-ID:
        <DB7PR06MB4409386F14FFAE2FCA822660AA810 at DB7PR06MB4409.eurprd06.prod.outlook.com>

Content-Type: text/plain; charset="Windows-1252"

Hi Martin,

Thank you for the answer.
I just thought there might be something about it in MITgcm I missed.

Best regards,
Igor

________________________________________
From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
Sent: 12 June 2020 10:30
To: MITgcm Support
Subject: Re: [MITgcm-support] Potential energy in MITgcm

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Hi Igor,

rhethorical question: what is potential energy in a GCM?

This is a bit complicated. You could just intergrate density vertically (and density or density anomaly can be saved via the diagnostics pkg), but you really only want to have available potential density, for which you need a reference state that is difficult (impossible?) to define for general case. So it?s always set-up specific.

Details of the actual computation also depend on details of your configuration (free surface linear/non-linear/r-star, etc.)

M.

> On 12. Jun 2020, at 11:23, Shevchenko, Igor <i.shevchenko at imperial.ac.uk> wrote:
>
> Dear MITgcm users,
>
> Is there a chance to diagnose potential energy in MITgcm?
>
> Best regards,
> Igor
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support

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