[MITgcm-support] [EXTERNAL] Curvilinear grid generation

[Yilang Xu]

Hi Dimitris,

Thank you for pointing out the regular lat/lon grid. However, I am thinking about a rectangular curvilinear grid under a polar stereographic projection. An example of the model domain that is relevant to this question is shown in the following paper (red lines as the boundaries in Figure 1): https://gmd.copernicus.org/articles/16/3355/2023/

The reason that I do not use the spherical polar grid for this case is because the horizontal spacing is quite small in the Southern end near the south pole. But I do not need that high resolution in the southern end, and this leads to unnecessary CFL constraints.

Thanks,
Yilang

From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Menemenlis, Dimitris (US 329B) <dimitris.menemenlis at jpl.nasa.gov>
Date: Tuesday, April 16, 2024 at 21:54
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] [EXTERNAL] Curvilinear grid generation
You don't often get email from dimitris.menemenlis at jpl.nasa.gov. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification>
If you are using a rectangular latitude/longitude grid, the easiest way to specify the grid is via a few parameters in the data files, e.g., as is done here:
https://github.com/MITgcm/MITgcm/blob/master/verification/lab_sea/input/data

# Gridding parameters
#
#   usingSphericalPolarGrid - On/Off flag for spherical polar coordinates
#   delX                    - Zonal grid spacing         (degrees)
#   delY                    - Meridional grid spacing    (degrees)
#   delZ                    - Vertical grid spacing      (m)
#   ygOrigin                - Southern boundary latitude (degrees)
#
 &PARM04
 usingSphericalPolarGrid=.TRUE.,
 delX=20*2.E0,
 delY=16*2.E0,
 delZ= 10., 10., 15., 20., 20., 25., 35., 50., 75.,
       100., 150., 200., 275., 350., 415., 450.,
       500., 500., 500., 500., 500., 500., 500.,
 ygOrigin=46.,
 xgOrigin=280.,
 rSphere = 6371.D3,
 &


On Apr 16, 2024, at 1:50 AM, Yilang Xu <yxu at whoi.edu<mailto:yxu at whoi.edu>> wrote:

Hi Dimitris,

Thank you for the reply. I am using a rectangular grid, which is for a regional modeling near Antarctica.

Cheers,
Yilang

From: MITgcm-support <mitgcm-support-bounces at mitgcm.org<mailto:mitgcm-support-bounces at mitgcm.org>> on behalf of Menemenlis, Dimitris (US 329B) <dimitris.menemenlis at jpl.nasa.gov<mailto:dimitris.menemenlis at jpl.nasa.gov>>
Date: Tuesday, April 16, 2024 at 00:52
To: mitgcm-support at mitgcm.org<mailto:mitgcm-support at mitgcm.org> <mitgcm-support at mitgcm.org<mailto:mitgcm-support at mitgcm.org>>
Subject: Re: [MITgcm-support] Curvilinear grid generation
What is the desired characteristics of your grid?  Would a latitude/longitude or a rectangular grid suffice for your application?

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