<div dir="ltr"><div>Hi,<br><br></div>Is it possible to make this file available too, in order to run the script:<br><br><div><div><div><div><div><div><div>AWIP32-fixed.grb</div><div><br></div><div>Rick<br></div></div></div></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 27, 2018 at 3:02 PM, Herbster, Christopher G. <span dir="ltr"><<a href="mailto:herbstec@erau.edu" target="_blank">herbstec@erau.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_-1460191892117467243WordSection1">
<p class="MsoNormal">Hi folks,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Here is a sequence of events that we are using to download some NARR data from NOMADS at NCDC:<u></u><u></u></p>
<p class="MsoNormal">We use the <a href="http://get-httpsubset.pl" target="_blank">get-httpsubset.pl</a> script from<u></u><u></u></p>
<p class="MsoNormal"><a href="https://nomads.ncdc.noaa.gov/guide/index.php?name=advanced#adv-httpsubset" target="_blank">https://nomads.ncdc.noaa.gov/<wbr>guide/index.php?name=advanced#<wbr>adv-httpsubset</a> and the Perl scripts from<u></u><u></u></p>
<p class="MsoNormal"><a href="http://www.cpc.ncep.noaa.gov/products/wesley/fast_downloading_grib.html" target="_blank">http://www.cpc.ncep.noaa.gov/<wbr>products/wesley/fast_<wbr>downloading_grib.html</a> to grab a handful of parameters from the NARR dataset.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">This gives us GRIB files like: <u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/narr-a_221_20101201_1200_000.sub.grb" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>narr-a_221_20101201_1200_000.<wbr>sub.grb</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I then used: ncl_convert2nc narr-a_221_20101201_1200_000.<wbr>sub.grb -nc4c -l<u></u><u></u></p>
<p class="MsoNormal">To make <u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/narr-a_221_20101201_1200_000.sub.nc4" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>narr-a_221_20101201_1200_000.<wbr>sub.nc4</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I did this for 30 years of data ending 12-31-2010.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">We then used an NCL script to do some calculations on a month of data, and write the results into a new file.<u></u><u></u></p>
<p class="MsoNormal">Here is the script:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/read_narr_ncar-help.ncl" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>read_narr_ncar-help.ncl</a>
<u></u><u></u></p>
<p class="MsoNormal">My apologies to those of you who actually know how to code in NCL. I am strictly an amateur at this.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Here is the file we created: <u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/D-Value_Monthly_Stats.2010.12.averages.1200.nc" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/D-<wbr>Value_Monthly_Stats.2010.12.<wbr>averages.1200.nc</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Our problem seems to be aligning the data to the map background, as I can show with the following images:<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The grey area in this image is supposed to be where the terrain is higher than the calculated value:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/narr-paper.000001.png" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>narr-paper.000001.png</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The data mask area is too far to the west, even extending out over the ocean.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">When we plot it in the Unidata IDV we get what we expect:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/IDV_4K_Mask_D-Val.png" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/IDV_<wbr>4K_Mask_D-Val.png</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Then we decided to try plotting it in Matlab as another test. We got:
<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/Matlab_Plot_NARR_Mask.jpg" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>Matlab_Plot_NARR_Mask.jpg</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">While I suspect that I am not doing something properly with the mapping of the data, I am also wondering about the results of making the NetCDF file from the ncl_convert command.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">First, is the compression lossy? I realized that the default compression is zero, so this step did not do much for disk space! (Actually made bigger files, but never mind.)<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">When I load the original GRIB file into the IDV it displays the region properly without any problem. When I try to load the original NetCDF file, the IDV does not seem to know the geographic region of the data.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">This can be seen in the following images:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/load-both-idv.png" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>load-both-idv.png</a> shows the Mean Sea Level Pressure data from both files. They appear to match.
However, when I added the second panel (NetCDF file), the IDV did not display the data properly, and did so only after I selected a predefined CONUS projection (as shown).<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">When I open the NetCDF file and plotted MSLP in a window by itself, I got this:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/load-netcdf-idv.png" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>load-netcdf-idv.png</a>
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I had to zoom way out to display this data. It knows where to put the data, but the IDV thinks the data should be in the white box area, I think. (I’m not really sure about this interpretation.)<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The questions I have are:<u></u><u></u></p>
<p class="m_-1460191892117467243MsoListParagraph"><u></u><span>1)<span style="font:7.0pt "Times New Roman"">
</span></span><u></u>Why does this happen?<u></u><u></u></p>
<p class="m_-1460191892117467243MsoListParagraph"><u></u><span>2)<span style="font:7.0pt "Times New Roman"">
</span></span><u></u>Is this related to my data masking and mapping problem, or are they separate issues?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thanks in advance for any help on any of these problems/questions.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Cheers,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Chris <u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">PS If you want to test our script, there is a month of data in this tar file:<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/faculty/herbster/demo/.hidden/NCL/sample-narr.tgz" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/demo/.hidden/NCL/<wbr>sample-narr.tgz</a>
<u></u><u></u></p>
<p class="MsoNormal">-- <u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Dr. Christopher G. Herbster<u></u><u></u></p>
<p class="MsoNormal">Associate Professor<u></u><u></u></p>
<p class="MsoNormal">Director of Science and Technology<u></u><u></u></p>
<p class="MsoNormal">for the ERAU Weather Center<u></u><u></u></p>
<p class="MsoNormal">Applied Aviation Sciences<u></u><u></u></p>
<p class="MsoNormal">Embry-Riddle Aeronautical Univ.<u></u><u></u></p>
<p class="MsoNormal">600 S. Clyde Morris Blvd.<u></u><u></u></p>
<p class="MsoNormal">Daytona Beach, FL 32114-3900<u></u><u></u></p>
<p class="MsoNormal"><u></u><u></u></p>
<p class="MsoNormal"> <a href="tel:(386)%20226-6444" value="+13862266444" target="_blank">386.226.6444</a> Office<u></u><u></u></p>
<p class="MsoNormal"><a href="tel:(386)%20226-6446" value="+13862266446" target="_blank">386.226.6446</a> Weather Center<u></u><u></u></p>
<p class="MsoNormal"><a href="http://wx.erau.edu/" target="_blank">http://wx.erau.edu/</a><u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Schedule at: <a href="http://wx.erau.edu/faculty/herbster/Schedules/" target="_blank">http://wx.erau.edu/faculty/<wbr>herbster/Schedules/</a><u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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