[MITgcm-support] MITgcm-support Digest, Vol 140, Issue 1

Sun Feb 1 09:46:39 EST 2015

Hi Matthew and Cristopher ,

I developed at the beginning the vorticity balance for a simple domain , a square domain . I saw that applying the curl to moment budget in the first 500 m where , at least in my domain, the baroclinicity effect are negligible, the value of Z3 reconstructed using the the advection term (coming from the um_advec) , stretching (coming from um_Coriolis) , and diffusion coming from (Um_diss) fits very well with the output of the model.The only problem seems to be present with baroclinicity term that doesn’t look to derive from UM_Dphx-Dx.

What do you think about?

marco

> Il giorno 01/feb/2015, alle ore 09:57, mitgcm-support-request at mitgcm.org ha scritto:
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> Today's Topics:
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>   1. Re: MITgcm-support Digest, Vol 139, Issue 30 (marco reale)
>   2. Re: MITgcm-support Digest, Vol 139, Issue 30 (Matthew Mazloff)
>   3. Re: vorticity balance (Christopher Pitt Wolfe)
>   4. Milankovitch cycles (Hadar Berman)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sat, 31 Jan 2015 18:05:32 +0100
> From: marco reale <reale.marco82 at gmail.com>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] MITgcm-support Digest, Vol 139, Issue 30
> Message-ID: <65677A7E-B902-4AA4-A545-B785B58AE007 at gmail.com>
> Content-Type: text/plain; charset="us-ascii"
> 
> Hi matt,
> 
> thanks a lot for the suggestion : my method computes correctly the stretching, diffusion and advection term : the term from the gradient of Eta vanishes  . I have only some problems with baroclinicity term : Do you refer to it when you talk about to pressure term?
> 
> cheers
> 
> Marco
> 
> 
> 
>> Il giorno 31/gen/2015, alle ore 18:00, mitgcm-support-request at mitgcm.org ha scritto:
>> 
>> note that if you are using spherical coordinates the discretization will cause the pressure term to not vanish, so you need to account for tha
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> Message: 2
> Date: Sat, 31 Jan 2015 09:50:11 -0800
> From: Matthew Mazloff <mmazloff at ucsd.edu>
> To: <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] MITgcm-support Digest, Vol 139, Issue 30
> Message-ID: <3B472044-6B8C-4DC5-881B-E5CEF40036B3 at ucsd.edu>
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> 
> Hi Marco
> 
> I don't know your setup, but if your term from Eta vanishes then I don't think my comment pertains to you.
> 
> What I was referring to is the fact that in calculus
> P_{xy} - P_{yx} = 0
> 
> But when discretized such that DX is a function of y this will not equal to zero. This can be a lowest order term for coarse resolution spherical coordinate models.
> 
> I have argued to myself that given the pressure solver method of the model, it makes sense to group this contribution into the stretching term. I tell myself that as resolution increases and DX goes to zero this error will be reduced, and W will be larger? I am very interested to hear other thoughts on how to attribute this term.
> 
> Matt
> 
> 
> 
> On Jan 31, 2015, at 9:05 AM, marco reale <reale.marco82 at gmail.com> wrote:
> 
>> Hi matt,
>> 
>> thanks a lot for the suggestion : my method computes correctly the stretching, diffusion and advection term : the term from the gradient of Eta vanishes  . I have only some problems with baroclinicity term : Do you refer to it when you talk about to pressure term?
>> 
>> cheers
>> 
>> Marco
>> 
>> 
>> 
>>> Il giorno 31/gen/2015, alle ore 18:00, mitgcm-support-request at mitgcm.org ha scritto:
>>> 
>>> note that if you are using spherical coordinates the discretization will cause the pressure term to not vanish, so you need to account for tha
>> 
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
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> ------------------------------
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> Message: 3
> Date: Sat, 31 Jan 2015 13:27:28 -0500
> From: Christopher Pitt Wolfe <c.l.p.wolfe at icloud.com>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] vorticity balance
> Message-ID: <77631ED6-5898-4E2A-BE23-78835CFD8ECF at icloud.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Matt & Marco:
> 
> If either of you happen to have the finite difference form of the vorticity equation written out (either as a document or as code), I think a lot of people would be interested in seeing it. I?ve worked out of few terms on my own, but I usually give up when I get to the advection terms ? 
> 
> Cheers,
> Christopher
> 
>> On Jan 31, 2015, at 12:50 PM, Matthew Mazloff <mmazloff at ucsd.edu <mailto:mmazloff at ucsd.edu>> wrote:
>> 
>> Hi Marco
>> 
>> I don't know your setup, but if your term from Eta vanishes then I don't think my comment pertains to you.
>> 
>> What I was referring to is the fact that in calculus
>> P_{xy} - P_{yx} = 0
>> 
>> But when discretized such that DX is a function of y this will not equal to zero. This can be a lowest order term for coarse resolution spherical coordinate models.
>> 
>> I have argued to myself that given the pressure solver method of the model, it makes sense to group this contribution into the stretching term. I tell myself that as resolution increases and DX goes to zero this error will be reduced, and W will be larger? I am very interested to hear other thoughts on how to attribute this term.
>> 
>> Matt
>> 
>> 
>> 
>> On Jan 31, 2015, at 9:05 AM, marco reale <reale.marco82 at gmail.com <mailto:reale.marco82 at gmail.com>> wrote:
>> 
>>> Hi matt,
>>> 
>>> thanks a lot for the suggestion : my method computes correctly the stretching, diffusion and advection term : the term from the gradient of Eta vanishes  . I have only some problems with baroclinicity term : Do you refer to it when you talk about to pressure term?
>>> 
>>> cheers
>>> 
>>> Marco
>>> 
>>> 
>>> 
>>>> Il giorno 31/gen/2015, alle ore 18:00, mitgcm-support-request at mitgcm.org <mailto:mitgcm-support-request at mitgcm.org> ha scritto:
>>>> 
>>>> note that if you are using spherical coordinates the discretization will cause the pressure term to not vanish, so you need to account for tha
>>> 
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org <mailto:MITgcm-support at mitgcm.org>
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support <http://mitgcm.org/mailman/listinfo/mitgcm-support>
>> 
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> Message: 4
> Date: Sun, 1 Feb 2015 10:56:58 +0200
> From: Hadar Berman <hadarberman at gmail.com>
> To: mitgcm-support at mitgcm.org
> Subject: [MITgcm-support] Milankovitch cycles
> Message-ID: <494D28DC-2BFA-4DC5-9392-C64FEDB9B2B1 at gmail.com>
> Content-Type: text/plain; charset=us-ascii
> 
> Dear all,
> 
> I am interested in running an ecological model for past climates. I was wandering if anyone has ever implemented Milankovitch cycles into the 3D model, and if so, is there any way to receive this code.
> 
> Thanks in advance,
> Hadar.
> 
> 
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> End of MITgcm-support Digest, Vol 140, Issue 1
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