<div dir="ltr"><div class="gmail_default" style="font-size:small">Hi Jacob,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">Welcome back to NCL. </div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">1) You do want to set SrcRegional to True if your source grid is not global. If the destination grid is also not global, then set DstRegional to True as well.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default">2) The regridding is done based on whatever lat/lon destination grid you give it. So, if you tell it to regrid to a "2.5x2.5" deg grid, then internally it generates a *global* 2.5 x 2.5 grid, regardless of what SrcRegional or DstRegional are set to. This doesn't hurt anything, but it can make your regridding go slower if you have a small regional area to regrid. </div><div class="gmail_default"><br></div><div class="gmail_default">If you don't want a global 2.5 x 2.5 grid generated under the hood, then you can <font face="arial, helvetica, sans-serif">optionally set "<pre style="display:inline!important"><font face="arial, helvetica, sans-serif">DstLLCorner</font>"<font face="arial, helvetica, sans-serif"> and </font>"</pre><pre style="display:inline!important"><font face="arial, helvetica, sans-serif">DstURCorner"</font> <font face="arial, helvetica, sans-serif">to the lower left and upper right corners of a lat/lon box that contains the area you want to regrid to. Internally, then, a 2.5 x 2.5 grid will be generated across these lat/lon limits only.</font></pre></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><pre style="display:inline!important"><font face="arial, helvetica, sans-serif"><br></font></pre></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><span style="white-space:pre">Here's what the ESMF_regrid (<a href="http://www.ncl.ucar.edu/Document/Functions/ESMF/ESMF_regrid.shtml">http://www.ncl.ucar.edu/Document/Functions/ESMF/ESMF_regrid.shtml</a>) </span></font><span style="white-space:pre;font-family:arial,helvetica,sans-serif">documentation says about the meaning of SrcRegional and DstRegional:</span></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><span style="white-space:pre"><br></span></font></div><div class="gmail_default"><li><b>SrcRegional</b> (default = False)<p>
By default, the ESMF regridding application assumes that a logically
rectangular grid is periodic. This means that it connects the ends of
the first dimension to form a sphere and allows extrapolation over the
pole. If this attribute is set to True, then the source grid is assumed
to NOT have a periodic connection and instead is considered just a
region of the sphere.
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<a name="DstRegional"></a>
</p></li><li><b>DstRegional</b> (default = False)<p>
By default, the ESMF regridding application assumes that a logically
rectangular grid is periodic. This means that it connects the ends of
the first dimension to form a sphere and allows extrapolation over the
pole. If this attribute is set to True, then the destination grid is
assumed to NOT have a periodic connection and instead is considered
just a region of the sphere. </p></li>3) Dennis Shea has written a nice overview that you can see at:</div><div class="gmail_default"><br></div><div class="gmail_default"><a href="https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview">https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview</a><br></div><div class="gmail_default"><br></div><div class="gmail_default">Please visit our examples page:</div><div class="gmail_default"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/ESMF.shtml">http://www.ncl.ucar.edu/Applications/ESMF.shtml</a><br></div><div class="gmail_default"> </div><div class="gmail_default">You can also see some regridding templates at:</div><div class="gmail_default"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/Templates/#ESMFRegriddingTemplates">http://www.ncl.ucar.edu/Applications/Templates/#ESMFRegriddingTemplates</a><br></div><div class="gmail_default"><br></div><div class="gmail_default">If you have problems getting your regridding script to work, please post back to ncl-talk and let us know. It helps if you can provide us with the script as you have it so far, and the data file (we can provide an ftp site for you to upload it to if necessary).</div><div class="gmail_default"><br></div><div class="gmail_default">Good luck,</div><div class="gmail_default"><br></div><div class="gmail_default">--Mary</div><div class="gmail_default"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Oct 26, 2015 at 12:49 PM, Jacob Klee (VirginiaPower - 1) <span dir="ltr"><<a href="mailto:jacob.klee@dom.com" target="_blank">jacob.klee@dom.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hello,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I am diving back into NCL after about a decade away, and have a few questions about regridding. I have gathered a few parameters (Z500hPa, MSLP, and SST) from
numerous reanalysis datasets, having already geographically subset all to (as close as possible) 85N, -180E, -10N, 180E. I intend to regrid them all to the NCEP R1 2.5x2.5deg grid.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Question 1) I assume that I will want to set option “SrcRegional” to True?
<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Question 2) Should I contract the destination grid to 82.5N, -180E, -7.5N, 180E as some of the rectilinear datasets will have 85N & -10N as their northern and
southernmost data (JRA-55 for ex), or does the script handle that for the user with the option “SrcRegional” set to true?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Question 3) Any recommendation on which interpolation method(s) would best suite each of the three data types?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">-- Jacob Klee<u></u><u></u></span></p>
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