Hello Wesley,<br><br>Thanks for your explanation of the 3 hour versus 6 hour accumulation problem with gfs_hd.<br><br>I tried your workaround, but it failed pretty quickly for me. I have never used wgrib or wgrib2 and I searched on the internet for some documentation, but I couldn't find much.<br>
<br>This is where if failed for me:<br><br>>sh<br>>[ -f IN.grb ] && rm IN.grb<br>>for f in (list of file from f03 to fNN)<br>sh: syntax error near unexpected token `('<br><br>Also, I believe that you would need to open the data file first, but I couldn't get that to work either:<br>
<br>>wgrib <a href="http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101202/gfs_hd_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101202/gfs_hd_00z</a><br>could not open file: <a href="http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101202/gfs_hd_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101202/gfs_hd_00z</a><br>
<br>So, I am not sure how to use this workaround. Any further help would be greatly appreciated.<br><br>Sincerely,<br><br><br>Jeff<br><br><br><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Message: 4<br>
Date: Wed, 01 Dec 2010 09:21:02 -0500<br>
From: Wesley Ebisuzaki <<a href="mailto:Wesley.Ebisuzaki@noaa.gov">Wesley.Ebisuzaki@noaa.gov</a>><br>
Subject: Re: [gradsusr] Plotting GFS_HD apcpsfc every 3 hours problems<br>
To: GrADS Users Forum <<a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a>><br>
Message-ID: <<a href="mailto:4CF659CE.3050106@noaa.gov">4CF659CE.3050106@noaa.gov</a>><br>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed<br>
<br>
Jeff,<br>
<br>
The "Joys of Compatibility" strikes again (old code expects 6 hour<br>
accumulations).<br>
Anyways there is a function in wgrib2 to make all the accumulations into<br>
3 hour chunks.<br>
<br>
1) put all the APCP records into one file (IN.grb) in order (f03 to<br>
fNN). Here is how to do it in sh.<br>
<br>
[ -f IN.grb ] && rm IN.grb<br>
for f in (list of file from f03 to fNN)<br>
do<br>
wgrib2 f -match ":APCP:" -append -grib IN.grb<br>
done<br>
<br>
IN.grb should contain the APCP from one forecast run starting from 3<br>
hour forecast to N hour forecast.<br>
<br>
2) Run wgrib2 to normalize the records.<br>
<br>
wgrib2 IN.grb -match ":APCP:" -set_grib_type c1 -ncep_norm precip.grb<br>
<br>
Wesley Ebisuzaki<br>
<br>
<br>
Jeff Chabot wrote:<br>
> Hello GrADS Users,<br>
><br>
> I am looking for help plotting 3 hr precip using gfs_hd (from<br>
> <a href="http://nomads.ncep.noaa.gov" target="_blank">nomads.ncep.noaa.gov</a> <<a href="http://nomads.ncep.noaa.gov" target="_blank">http://nomads.ncep.noaa.gov</a>>) every three<br>
> hours. I have it working fine using nam and gens. However, when I<br>
> plot apcpsfc using gfs or gfs_hd, every other hour it seems like it is<br>
> plotting 3 hour precip, then 6 hour precip, and back to 3 hour, then 6<br>
> hour precip all the way through the 65 points. This makes the precip<br>
> appear to pulsate, every other frame. I have attached two images to<br>
> illustrate the problem. Does anyone have a work around for this<br>
> issue? The problem is isolated to just gfs data (both gfs_hd and<br>
> gfs), but doesn't happen with GFS Ensembles.<br>
><br>
> Versions:<br>
> Grid Analysis and Display System (GrADS) Version 2.0.a9<br>
> Fedora-13-x86_64<br>
><br>
> Data source example:<br>
><br>
> sdfopen:<br>
> <a href="http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101130/gfs_hd_12z" target="_blank">http://nomads.ncep.noaa.gov:9090/dods/gfs_hd/gfs_hd20101130/gfs_hd_12z</a><br>
><br>
> Attached files:<br>
> precip_US_6.png (appears to show 3 hours of precip)<br>
> precip_US_7.png (appears to show 6 hours of precip)<br>
><br>
> Here is my attempt to work around the issue for just gfs_hd / gfs,<br>
> though it doesn't solve the problem:<br>
> (Note: This is the section of my .gs file related to my work around<br>
> attempt):<br>
><br>
> *grads code<br>
><br>
> t = 1<br>
> t0 = 0<br>
> alt = -1<br>
> while ( t <= 65 )<br>
><br>
> 'set t 't<br>
> 'define precip = apcpsfc/25.4'<br>
> if alt > 0 then<br>
> 'define product = precip(t='t')'<br>
> 'define over4= precip(t='t')'<br>
> endif<br>
> if alt < 0 then<br>
> 'define product = (precip(t=t) - precip(t=t0))'<br>
> 'define over4 = (precip(t=t) - precip(t=t0))'<br>
> endif<br>
><br>
> *more grads code<br>
><br>
> t = t+1<br>
> say ' = 't<br>
> t0 = t0+1<br>
> say ' = 't0<br>
> alt = alt * -1<br>
> endwhile<br>
><br>
> Any help here would be greatly appreciated. Thanks again.<br>
><br>
> Sincerely,<br>
><br>
><br>
> Jeff Chabot<br>
> <a href="mailto:jsc219@gmail.com">jsc219@gmail.com</a> <mailto:<a href="mailto:jsc219@gmail.com">jsc219@gmail.com</a>><br>
> <a href="http://jeffsweatherservice.com" target="_blank">http://jeffsweatherservice.com</a><br>
<br>
</blockquote><br></div><br>