[MITgcm-support] MITgcm-support Digest, Vol 194, Issue 26

David Vishny davidvish at gmail.com
Tue Aug 27 14:02:37 EDT 2019


Hi Martin,

My latest checkpoint in tag-index is 65u. I’ve attached 3 folders (code, binary files and namelist files).


Thanks,

David

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> On Aug 27, 2019, at 11:00 AM, mitgcm-support-request at mitgcm.org wrote:
> 
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> Today's Topics:
> 
>   1. On the set up of the OBCS volume conservation in a	regional
>      simulation with curvilinear grid (=?gb18030?B?d2hhbGU=?=)
>   2. Re: On the set up of the OBCS volume conservation in a
>      regional simulation with curvilinear grid (Martin Losch)
>   3. Re: MITgcm-support Digest, Vol 194, Issue 17 (Martin Losch)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 27 Aug 2019 10:27:35 +0800
> From: "=?gb18030?B?d2hhbGU=?=" <250107302 at qq.com>
> To: "=?gb18030?B?bWl0Z2NtLXN1cHBvcnQ=?=" <mitgcm-support at mitgcm.org>
> Subject: [MITgcm-support] On the set up of the OBCS volume
> 	conservation in a	regional simulation with curvilinear grid
> Message-ID: <tencent_A8ADE27C5BAABCC481A0605E47A84540C808 at qq.com>
> Content-Type: text/plain; charset="gb18030"
> 
> Dear friends,
> 
> I am a little confused by the setting of volume conservation in a regional simulation. 
> 
> I had set up a regional model in Prydz Bay based on the spherical grid (usingSphericalPolarGrid=.TRUE.,). By following the suggestion in historical emails, the volume conservation can be set as follows:
> 
> V*DRF*DXG*hFacS?U*DRF*DYG*hFacW; Here, the volume calculated by these flux at the OBCS should be 0 to keep the volume conservation;
> 
> Now, I want to set up a regional model based on the curvilinear grid (usingCurvilinearGrid=.TRUE.). As I see, the velocity in the curvilinear grid are rotated by the AngleCS/SN.data files. So, I am a little confused with what should I do with the velocity field applied at the OBCS. Should I rotate the velocity fields applied at the OBCS to keep the volume conservation in a curvilinear grid simulation. Or, Should I just apply the velocity filed as what I had did in the spherical grid simulation, and the model can adjust the velocity fields by itself.
> 
> Cheers
> 
> Chengyan
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> ------------------------------
> 
> Message: 2
> Date: Tue, 27 Aug 2019 11:01:04 +0200
> From: Martin Losch <Martin.Losch at awi.de>
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] On the set up of the OBCS volume
> 	conservation in a regional simulation with curvilinear grid
> Message-ID: <AC83E9EE-E82C-4BED-A554-0EDBFB9D55D9 at awi.de>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi Chengyan,
> 
> AngelCS/SN are the cos/sin of the angle the grid makes with geographical north.The velocities are still aligned with the grid, so that **only if** you want velocities in the zonal and meridional direction you need to rotate them.
> 
> The same combination of variables (as you noted) describe the flux through the open boundary conditions in any grid.
> 
> If you want to use velocities from a polar spherical grid as open boundary conditions for a general curvilinear grid that is not aligned with the meridians and parallels, then you need to rotate these velocities into the direction of the curvilinear grid (which is given locally by AngleCS/SN).
> 
> Does that make sense?
> 
> Martin
> 
>> On 27. Aug 2019, at 04:27, whale <250107302 at qq.com> wrote:
>> 
>> Dear friends,
>> I am a little confused by the setting of volume conservation in a regional simulation.
>> I had set up a regional model in Prydz Bay based on the spherical grid (usingSphericalPolarGrid=.TRUE.,). By following the suggestion in historical emails, the volume conservation can be set as follows:
>> V*DRF*DXG*hFacS?U*DRF*DYG*hFacW; Here, the volume calculated by these flux at the OBCS should be 0 to keep the volume conservation;
>> Now, I want to set up a regional model based on the curvilinear grid (usingCurvilinearGrid=.TRUE.). As I see, the velocity in the curvilinear grid are rotated by the AngleCS/SN.data files. So, I am a little confused with what should I do with the velocity field applied at the OBCS. Should I rotate the velocity fields applied at the OBCS to keep the volume conservation in a curvilinear grid simulation. Or, Should I just apply the velocity filed as what I had did in the spherical grid simulation, and the model can adjust the velocity fields by itself.
>> Cheers
>> Chengyan
>> 
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> 
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Tue, 27 Aug 2019 12:09:32 +0200
> From: Martin Losch <Martin.Losch at awi.de>
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] MITgcm-support Digest, Vol 194, Issue 17
> Message-ID: <088C4F43-119B-4288-BF9A-A8E52C28A201 at awi.de>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi David,
> 
> I can?t see anything particularly bad in your files.
> 
> I tried to compile and run, but I am missing all sorts of forcing files, so that no ice forms and the LSR solver does not have anything to do (and no nans).
> 
> I suggest that you prepare a configuration somewhere for me to download (i.e. code and input directories and forcing files, topography, inital conditions ...), that runs for at least a few time steps ( and produces NaN when pkg/seaice is used), and I can try to figure out the problem. It?s probably something simple, if it happens in the first timestep.
> 
> I don?t know what this version number refers to, I was thinking of the latest checkpoint in doc/tag-index, do you know what that is?
> 
> More general comments about your sea ice parameters (that will not affect your problem, I am afraid)
> 
> LSR_ERROR             = 1.E-17, # that?s an overkill. I suggest 1e-5, or 1e-6
> SEAICE_OLx = 1, # with recent code, you don?t need this anymore
> SEAICE_OLy = 1,
> #
> SEAICE_salt0          = 4.,
> # the next three are default:
> SEAICEadvHeff         = .TRUE., 
> SEAICEadvArea         = .TRUE.,
> SEAICEadvSnow         = .TRUE.,
> # with a stable advection scheme (e.g. SEAICEadvScheme = 77), you don?t need the diffusion of seaice (I find diffusion of sea ice difficult to imagine)
> SEAICEdiffKhHeff       = 100.,
> SEAICEdiffKhArea       = 100.,
> SEAICEdiffKhSnow       = 100.,
> SEAICEdiffKhSalt       = 100.,
> 
> Martin
> 
> 
>> On 26. Aug 2019, at 18:50, David Vishny <davidvish at gmail.com> wrote:
>> 
>> Hi Martin,
>> 
>> -My model version is 1.2242. 
>> 
>> -From the working configuration, I changed the grid from 72 x 140 x 29 to 128 x 64 x 15 (as in the biogeochemistry tutorial), and went from 4 x 7 processors to 4 x 4 processors.
>> 
>> -I also switched from simplified topography to the realistic global topography of the biogeochem tutorial, modified the EXF forcing files, and changed all the viscosities and diffusivities in the ?data" file to match those in the analogous file from the biogeochemistry tutorial.
>> 
>> -To avoid numerical instability during testing, I made the time-steps very tiny, switching from 14400 to 3200.
>> 
>> 
>> -I?ve attached two namelist files and three code directory files that might be relevant to understand my setup.
>> 
>> <packages.conf><data.seaice><data><CPP_OPTIONS.h><SEAICE_OPTIONS.h>
>> 
>> 
>> Thanks,
>> 
>> David
>> 
>>> 
>>> Message: 1
>>> Date: Sat, 24 Aug 2019 08:55:57 +0200
>>> From: Martin Losch <Martin.Losch at awi.de>
>>> To: <mitgcm-support at mitgcm.org>
>>> Subject: Re: [MITgcm-support] Sea ice dynamics causing model to output
>>> 	NaN's	after changing grid configuration
>>> Message-ID: <2129627E-3B99-43CB-A277-57C245DABE04 at awi.de>
>>> Content-Type: text/plain; charset="utf-8"
>>> 
>>> Hi David,
>>> I would need more details to be able to help. Configuration (code directory, namelist files, version of model), and what exactly you changed from a working configuration 
>>> 
>>> Martin
>>> 
>>>> On 24. Aug 2019, at 00:07, David Vishny <davidvish at gmail.com> wrote:
>>>> 
>>>> To whom it may concern,
>>>> 
>>>> I recently changed the grid configuration in my model setup, and now the model outputs all NaN?s after a single time-step if sea ice dynamics are enabled, even though there is no sea ice to begin with. If I disable sea ice dynamics, it appears that no problems occur. Thus, my advisor Malte Jansen and I believe the LSR solver is producing NaN?s. 
>>>> 
>>>> I know one parameter related to the LSR solver is the LSR error. For any given grid configuration, could the solver crash due to an LSR error that is either too high or too low? Are there any other parameters I should be playing around with that are related to the LSR solver? 
>>>> 
>>>> 
>>>> Thanks,
>>>> 
>>>> David Vishny
>>>> _______________________________________________
>>>> MITgcm-support mailing list
>>>> MITgcm-support at mitgcm.org
>>>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> 
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> End of MITgcm-support Digest, Vol 194, Issue 26
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