<html><head></head><body><div class="ydp23d9ce3cyahoo-style-wrap" style="font-family:bookman old style, new york, times, serif;font-size:16px;"><div><div dir="ltr" data-setdir="false"><span><div dir="ltr" data-setdir="false">Dear Dave,</div><div><br></div><div>Thank you for sharing your experience.</div><div><br></div><div>I’ll try converting GRIB2 to NetCDF using the commands you suggested. Appreciate the tip about CDO metadata and the article reference.</div></span></div><div><br></div><div class="ydp23d9ce3csignature"><div dir="ltr" style="font-family:old times, serif;font-size:16px;"><div><div dir="ltr" style="color:rgb(0, 0, 0);font-family:old times, serif;font-size:16px;"><i><font size="2">-----------------------------------------------------------------------------</font></i></div><div dir="ltr" style="color:rgb(0, 0, 0);font-family:old times, serif;font-size:16px;"> <div><div style="color:rgb(0, 0, 0);font-family:serif;font-size:16px;"><div dir="ltr"><i><font size="2">Best regards,</font></i></div><div dir="ltr"><i><font size="2">Ehsan Taghizadeh</font></i></div></div></div></div></div></div></div></div>
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On Sunday, November 9, 2025 at 09:08:48 AM PST, Dave Allured - NOAA Affiliate <dave.allured@noaa.gov> wrote:
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<div><div id="ydp23d9ce3cyiv5918719019"><div><div dir="ltr"><div>Ehsan, I get the same error with NCL on Mac OS. The input file is GRIB2. NCL support for GRIB2 is badly out of date.</div><div><br clear="none"></div><div>The easy workaround is to convert GRIB2 to Netcdf, before reading with NCL. These two different programs gave good results for me. CDO made better metadata. You can skip the format and compression options if you don't care. There are also some other modern programs to do this.</div><br clear="none">cdo -f nc4c -z zip_3 copy input_file <a shape="rect" href="http://output_file.nc" rel="nofollow" target="_blank">output_file.nc</a><br clear="none">grib_to_netcdf -k4 -d3 -D NC_FLOAT -o <a shape="rect" href="http://output_file.nc" rel="nofollow" target="_blank">output_file.nc</a> input_file<div><br clear="none"></div><div>Here is a nice article on converting GRIB/GRIB2 to Netcdf.</div><div><a shape="rect" href="https://confluence.ecmwf.int/display/OIFS/How+to+convert+GRIB+to+netCDF" rel="nofollow" target="_blank">https://confluence.ecmwf.int/display/OIFS/How+to+convert+GRIB+to+netCDF</a><br clear="none"><div><div dir="ltr"><br clear="none"></div><br clear="none"><div id="ydp23d9ce3cyiv5918719019yqt46403" class="ydp23d9ce3cyiv5918719019yqt3408175108"><div class="ydp23d9ce3cyiv5918719019gmail_quote ydp23d9ce3cyiv5918719019gmail_quote_container"><div dir="ltr" class="ydp23d9ce3cyiv5918719019gmail_attr">On Sat, Nov 8, 2025 at 7:51 PM Ehsan Taghizadeh via ncl-talk <<a shape="rect" href="mailto:ncl-talk@mailman.ucar.edu" rel="nofollow" target="_blank">ncl-talk@mailman.ucar.edu</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex;" class="ydp23d9ce3cyiv5918719019gmail_quote"><div><div style="font-size:16px;font-family:old times, serif;"><div dir="ltr"><div><div style="font-family:old times, serif;">Hello,</div><div dir="ltr" style="font-family:old times, serif;">I tried to read the <i>tp</i> variable from an <span><span style="font-family:old times, serif;font-size:16px;">ECMWF</span></span> file (attached) (WMO Recommended data option on the website of <span><a shape="rect" href="https://www.ecmwf.int/en/forecasts/datasets" style="color:rgb(75,93,255);font-family:old times, serif;font-size:16px;" rel="nofollow" target="_blank">ECMWF</a></span>), but I encountered the following error.</div><div dir="ltr" style="font-family:old times, serif;"><br clear="none"></div><div dir="ltr" style="font-family:old times, serif;">"""</div><div dir="ltr"><div><div><font face="courier new, courier, monaco, monospace, sans-serif">ncl: /home/conda/feedstock_root/build_artifacts/jasper_1754514279376/work/src/libjasper/base/jas_init.c:919: jas_get_ctx_internal: Assertion `ctx' failed.</font></div><div><font face="courier new, courier, monaco, monospace, sans-serif">Aborted (core dumped)</font></div></div></div><div dir="ltr" style="font-family:old times, serif;">"""</div>
<p style="font-family:old times, serif;">A couple of points I should mention:</p>
<p style="font-family:old times, serif;">1. I installed conda and NCL on two different servers, but the same issue occurred.</p>
<p style="font-family:old times, serif;">2. This issue also happened, for example, when I tried to read "PRES_P0_L1_GLL0" from sp files on ECMWF.</p>
<p style="font-family:old times, serif;">Any help would be greatly appreciated. The script and sample file are attached.</p></div></div><div style="font-family:old times, serif;"><div dir="ltr" style="font-family:serif;font-size:16px;"><div><div dir="ltr" style="color:rgb(0,0,0);font-family:serif;font-size:16px;"><i><font size="2">-----------------------------------------------------------------------------</font></i></div><div dir="ltr" style="color:rgb(0,0,0);font-family:serif;font-size:16px;"> <div><div style="color:rgb(0,0,0);font-family:serif;font-size:16px;"><div dir="ltr"><i><font size="2">Best regards,</font></i></div><div dir="ltr"><i><font size="2">Ehsan Taghizadeh</font></i></div><div dir="ltr"><i><font size="2">Ph.D. Student in Natural Resources & Environmental Studies (NRES),</font></i></div><div dir="ltr"><i><font size="2"> University of Northern British Columbia (UNBC)</font></i></div></div></div></div></div></div></div></div></div>
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