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<p class="MsoNormal"><span style="font-size:11.0pt">Hi Dimitris, <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">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):
<a href="https://gmd.copernicus.org/articles/16/3355/2023/">https://gmd.copernicus.org/articles/16/3355/2023/</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">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. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Yilang <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">MITgcm-support <mitgcm-support-bounces@mitgcm.org> on behalf of Menemenlis, Dimitris (US 329B) <dimitris.menemenlis@jpl.nasa.gov><br>
<b>Date: </b>Tuesday, April 16, 2024 at 21:54<br>
<b>To: </b>MITgcm Support <mitgcm-support@mitgcm.org><br>
<b>Subject: </b>Re: [MITgcm-support] [EXTERNAL] Curvilinear grid generation<o:p></o:p></span></p>
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<span style="font-size:9.0pt;font-family:"Segoe UI",sans-serif;color:#212121">You don't often get email from dimitris.menemenlis@jpl.nasa.gov.
<a href="https://aka.ms/LearnAboutSenderIdentification">Learn why this is important</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">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:
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><a href="https://github.com/MITgcm/MITgcm/blob/master/verification/lab_sea/input/data">https://github.com/MITgcm/MITgcm/blob/master/verification/lab_sea/input/data</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># Gridding parameters<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">#<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># usingSphericalPolarGrid - On/Off flag for spherical polar coordinates<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># delX - Zonal grid spacing (degrees)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># delY - Meridional grid spacing (degrees)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># delZ - Vertical grid spacing (m)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"># ygOrigin - Southern boundary latitude (degrees)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">#<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> &PARM04<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> usingSphericalPolarGrid=.TRUE.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> delX=20*2.E0,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> delY=16*2.E0,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> delZ= 10., 10., 15., 20., 20., 25., 35., 50., 75.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> 100., 150., 200., 275., 350., 415., 450.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> 500., 500., 500., 500., 500., 500., 500.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> ygOrigin=46.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> xgOrigin=280.,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> rSphere = 6371.D3,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"> &<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">On Apr 16, 2024, at 1:50 AM, Yilang Xu <<a href="mailto:yxu@whoi.edu">yxu@whoi.edu</a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">Hi Dimitris,</span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">Thank you for the reply. I am using a rectangular grid, which is for a regional modeling near Antarctica.</span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">Cheers,</span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">Yilang<span class="apple-converted-space"> </span></span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:12.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt">From:<span class="apple-converted-space"> </span></span></b><span style="font-size:12.0pt">MITgcm-support <<a href="mailto:mitgcm-support-bounces@mitgcm.org">mitgcm-support-bounces@mitgcm.org</a>>
on behalf of Menemenlis, Dimitris (US 329B) <<a href="mailto:dimitris.menemenlis@jpl.nasa.gov">dimitris.menemenlis@jpl.nasa.gov</a>><br>
<b>Date:<span class="apple-converted-space"> </span></b>Tuesday, April 16, 2024 at 00:52<br>
<b>To:<span class="apple-converted-space"> </span></b><a href="mailto:mitgcm-support@mitgcm.org">mitgcm-support@mitgcm.org</a><span class="apple-converted-space"> </span><<a href="mailto:mitgcm-support@mitgcm.org">mitgcm-support@mitgcm.org</a>><br>
<b>Subject:<span class="apple-converted-space"> </span></b>Re: [MITgcm-support] Curvilinear grid generation<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt">What is the desired characteristics of your grid? Would a latitude/longitude or a rectangular grid suffice for your application?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
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