<div dir="ltr"><div><div>Scott,<br><br></div><div>For these complicated variable, the g2ctl/alt_g2ctl makes variable<br></div><div>names that are too long for grads. You can edit the ctl files to<br></div><div>make shorter names but it is easier to use alt_g2ctl and the<br></div><div>-short option. I am going to focus on alt_g2ctl because it<br></div><div>has the most timing options.<br></div><div><br></div><div>GrADS has only 1 time dimension. Grib files can have several<br></div><div>time dimensions. One goal of alt_g2ctl is to map one<br></div><div>of the grib times to a the GrADS time.<br></div><div><br><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:240-246 hour acc fcst<br><br></span></div><div><span style="font-size:9pt;font-family:"Courier New"">In the above field, there are 3 possible time variables.<br><br></span></div><div><span style="font-size:9pt;font-family:"Courier New"">1) start of the model run time (or analysis time).<br><br></span></div><div><span style="font-size:9pt;font-family:"Courier New""> alt_g2ctl: -0 ignore 240-246 hours in the variable name<br></span></div><div><span style="font-size:9pt;font-family:"Courier New""> -0t "240-246 hour acc" in the variable name<br><br></span></div><div><span style="font-size:9pt;font-family:"Courier New"">2) start of averaging/accumulation period (240 hours + start of run time)<br></span></div><div><span style="font-size:9pt;font-family:"Courier New""> alt_g2ctl: -b ignore 240-246 hours in the variable name<br></span></div><div><span style="font-size:9pt;font-family:"Courier New""> -bt "240-246 hour acc" in the variable name<br><br></span></div><div><span style="font-size:9pt;font-family:"Courier New"">3) end of averaging/accumulation period (246 hours + start of run time)<br> </span><br><div><span style="font-size:9pt;font-family:"Courier New""> alt_g2ctl: -e ignore 240-246 hours in the variable name<br></span></div><span style="font-size:9pt;font-family:"Courier New""> -et "240-246 hour acc" in the variable name</span><span style="font-size:9pt;font-family:"Courier New""></span></div><div><span style="font-size:9pt;font-family:"Courier New""><br></span></div></div><div>So the meaning of the time is controlled by the option to alt_g2ctl.<br></div><div>If you forgot the options to alt_g2ctl, the options used are listed<br></div><div>in the ctl file.</div><div><br></div><div> Wesley<br></div><div><div><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Mar 13, 2018 at 4:12 PM, RENTSCHLER, SCOTT A GS-12 USAF ACC 16 WS/WXNM <span dir="ltr"><<a href="mailto:scott.rentschler.1@us.af.mil" target="_blank">scott.rentschler.1@us.af.mil</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="gmail-m_-908097445798119761MsoPlainText">All - <u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">I'm generating some post-processed information based off an ensemble. So for example, I might be generating the following parameters:<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:240-246 hour acc fcst:prob >2:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:240-246 hour acc fcst:prob >4:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:234-246 hour acc fcst:prob >4:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:234-246 hour acc fcst:prob >6:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:222-246 hour acc fcst:prob >2:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:222-246 hour acc fcst:prob >6:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText">…and I’m writing these fields in GriB2 format. In this example, I’m generating the data off of the GFS ensemble, writing out the information every 6 hours, with data valid at that forecast hour. So the above records appear in the
246 hour forecast file.<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">Note that we have a couple of fields then that, when using g2ctl, or even alt_g2ctl, would have identical variable names as they only differ in the accumulation period –<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:240-246 hour acc fcst:prob >2:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:222-246 hour acc fcst:prob >2:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New""><u></u> <u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:240-246 hour acc fcst:prob >4:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:234-246 hour acc fcst:prob >4:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New""><u></u> <u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:234-246 hour acc fcst:prob >6:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW Total Snowfall [prob]:surface:222-246 hour acc fcst:prob >6:probability forecast<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">The g2ctl utility outputs the following entries into the control file:<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW2e3GTsfc 0,1,0 a1,2 0,1,29,1 ** surface prob >2 Total Snowfall [prob]<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW4e3GTsfc 0,1,0 a1,4 0,1,29,1 ** surface prob >4 Total Snowfall [prob]<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOW6e3GTsfc 0,1,0 a1,6 0,1,29,1 ** surface prob >6 Total Snowfall [prob]</span><u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">The alt_gt2ctl:<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOWdprob_>2dprobability_<wbr>forecastsfc 0 0 "ASNOW.prob_>2.probability_<wbr>forecast:surface" * ASNOW.prob_>2.probability_<wbr>forecast:surface<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOWdprob_>4dprobability_<wbr>forecastsfc 0 0 "ASNOW.prob_>4.probability_<wbr>forecast:surface" * ASNOW.prob_>4.probability_<wbr>forecast:surface<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">ASNOWdprob_>6dprobability_<wbr>forecastsfc 0 0 "ASNOW.prob_>6.probability_<wbr>forecast:surface" * ASNOW.prob_>6.probability_<wbr>forecast:surface<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New""><u></u> <u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText">…and alt_g2ctl using the “–short” flag:<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">v1 0 0 "ASNOW.prob_>2.probability_<wbr>forecast:surface"<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">v2 0 0 "ASNOW.prob_>4.probability_<wbr>forecast:surface"<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:9pt;font-family:"Courier New"">v3 0 0 "ASNOW.prob_>6.probability_<wbr>forecast:surface"<u></u><u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText" style="margin-left:0.5in"><span style="font-size:10pt;font-family:"Courier New""><u></u> <u></u></span></p>
<p class="gmail-m_-908097445798119761MsoPlainText">My problem is that I’m unsure how to reference the different accumulation periods for the given parameters. If I were to create a template for a 246 hour forecast period, and within the GrADS command line interface, input “set t=42”,
and try to display one of the above parameters, how do I know which one I’m displaying and how does one switch to a different accumulation period? I’m hoping to avoid creating new files containing subsets of the above data, but at the moment I’m not sure
how to work around it. Is there a way to give each accumulation period a unique ID or an appropriate mechanism for identifying differing accumulation periods for a given parameter?<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">Thanks!<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">Scott<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">//Signed//<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">Scott Rentschler, Meteorologist<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">Fine Scale / Ensemble Models Team<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">557th Weather Wing, 16WS/WXN<u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText">DS: 271-3331 Comm: <a href="tel:%28402%29%20294-3331" value="+14022943331" target="_blank">(402) 294-3331</a><u></u><u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
<p class="gmail-m_-908097445798119761MsoPlainText"><u></u> <u></u></p>
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