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

Mon Feb 2 14:04:20 EST 2015

Hi Marco,

I seem to remember that when I did something similar I had to account for
both the baroclinic pressure term and the surface pressure term. There was
something nontrivial but I can't remember what it was. Unfortunately I am
away on travel and will not be able to look into it further until next 
month.
I'm not sure if this is related to your problem or not.

Mike

On 2/1/2015 9:46 AM, marco reale wrote:
> 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:
>>
>>    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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>> ------------------------------
>>
>> 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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