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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>I’m replying to my own question here, so others can find the solution. Solved. Tags for searching: hourly OBS nudging, OBSGRID, WRF 3.3. Solution first, statement of the problem below.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='color:#1F497D'>SOLUTION</span></b><span style='color:#1F497D'>:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>In namelist.wps, set (among other settings):<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>&share<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>interval_seconds = 21600 <o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='color:#1F497D'>to match your input GRIB data (every 6 hours for my data).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Make your <b>obs_filename</b> (</span><span style='font-family:"Courier New"'>OBS:*</span><span style='color:#1F497D'>, little_r format) files each contain <b>only 1 hour of data</b>. This conflicts somewhat with the statement in the <a href="http://www.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users_guide_chap7.htm#namelist">WRF v3.3 Users Guide</a>, Chapter 7, under OBSGRID Namelist: "Ideally there should be an <b>obs_filename</b> for each time period for which an objective analysis is desired." I suppose I should interpret “objective analysis” as <i>either</i> the 3D objective analysis or the 2D surface analysis.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I believe it should say that there should be an obs_filename for each <b>intf4d</b> (surface analysis) period. This is the key. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>In namelist.obsgrid, set (among other settings):<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal>&record1<o:p></o:p></p><p class=MsoNormal>interval = 21600<o:p></o:p></p><p class=MsoNormal>&record2<o:p></o:p></p><p class=MsoNormal>obs_filename = path/to/OBS<o:p></o:p></p><p class=MsoNormal>&record7<o:p></o:p></p><p class=MsoNormal>f4d = .TRUE.<o:p></o:p></p><p class=MsoNormal>intf4d = 3600<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='color:#1F497D'>This will produce </span><span style='font-family:"Courier New"'>OBS_DOMAIN101</span> <span style='color:#1F497D'>with 1 hour of data (+/- 30 minutes from the start time); </span><span style='font-family:"Courier New"'>OBS_DOMAIN102</span> <span style='color:#1F497D'>with 5 hours of data; </span><span style='font-family:"Courier New"'>OBS_DOMAIN103</span> <span style='color:#1F497D'>with 1 hour of data (+/- 30 minutes from start + interval [6 hours]); etc.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>You must concatenate all the </span><span style='font-family:"Courier New"'>OBS_DOMAIN1??</span> <span style='color:#1F497D'>files into a single </span><span style='font-family:"Courier New"'>OBS_DOMAIN101</span> <span style='color:#1F497D'>file in the WRF run directory. The Users Guide does not explicitly state this, though the latest tutorial does.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>auxinput11_interval_m</span> <span style='color:#1F497D'>is the minimum time interval you would like to check for new observations. If you want to nudge every hour, set this to 3600. Note that this is listed in </span><span style='font-family:"Courier New"'>test/em_real/README.obs_fdda</span><span style='color:#1F497D'> as </span><span style='font-family:"Courier New"'>auxinput11_interval_<b>s</b> = 180</span><span style='color:#1F497D'>, (180 <i>seconds</i>) which I believe is a typo. They problem meant 180 minutes (3 hours).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>auxinput11_end_h</span> <span style='color:#1F497D'>is the time at which you want to WRF stop reading </span><span style='font-family:"Courier New"'>OBS_DOMAIN101</span><span style='color:#1F497D'>. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='color:#1F497D'>PROBLEM</span></b><span style='color:#1F497D'>:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Following the WRF v3.3 Users Guide, Chapter 7, my <b>obs_filename</b> (</span><span style='font-family:"Courier New"'>OBS:*</span><span style='color:#1F497D'>, little_r format) files each contained 6 hours of data (to match <b>interval</b> = 21600). <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>At each <b>intf4d</b> time interval, OBSGRID opens an <b>obs_filename</b> file with the current time-stamp. It DOES NOT check for the existence of the file before it opens the file. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>So if your <b>obs_filename</b> (little_r) files each contain 6 hours of data, then at hour +1 it opens (and thus creates) a file with that time-stamp. Of course it's empty (newly created) so no data are read, and no data are output to the </span><span style='font-family:"Courier New"'>OBS_DOMAIN*</span> <span style='color:#1F497D'>file for that hour. If you started with <b>obs_filename</b> files like this:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 650M Aug 25 10:02 OBS:2008-01-29_12<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 630M Aug 25 10:10 OBS:2008-01-29_18<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 650M Aug 25 10:16 OBS:2008-01-30_00<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Then after OBSGRID.EXE had run, you'll have files like this:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 650M Aug 25 10:02 OBS:2008-01-29_12<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:03 OBS:2008-01-29_13<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:05 OBS:2008-01-29_14<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:06 OBS:2008-01-29_15<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:07 OBS:2008-01-29_16<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:08 OBS:2008-01-29_17<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 630M Aug 25 10:10 OBS:2008-01-29_18<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:10 OBS:2008-01-29_19<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:12 OBS:2008-01-29_20<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:13 OBS:2008-01-29_21<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:14 OBS:2008-01-29_22<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 0 Aug 25 10:15 OBS:2008-01-29_23<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Courier New"'>-rw-rw-rw- 1 username 650M Aug 25 10:16 OBS:2008-01-30_00<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>and your OBS_DOMAIN1?? files will contain only data +/- 30 minutes from each <b>interval</b> (each 6 hours). <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Bart<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> wrf-users-bounces@ucar.edu [mailto:wrf-users-bounces@ucar.edu] <b>On Behalf Of </b>Bart Brashers<br><b>Sent:</b> Wednesday, August 24, 2011 5:09 PM<br><b>To:</b> wrf-users@ucar.edu<br><b>Cc:</b> wrfhelp@ucar.edu<br><b>Subject:</b> [Wrf-users] OBS nudging<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a few questions about using OBS nudging in WRF v3.3. I’m using the 12km NAM data, which comes in 6 hour intervals. WPS ran fine, and I have met_em files every 6 hours.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have processed MADIS data to little_r format, and named the files OBS:YYYY-MM-DD_HH. Each file contains 6 hours of data, which I’ve confirmed via grep (e.g. “grep 200801 OBS:2008-01-29_18 | cut -c 327-336 | sort | uniq” shows the right time-stamps).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>1. OBSGRID.EXE creates OBS_DOMAIN101, OBSDOMAIN102, etc. But each file contains only ONE hour’s data (the analysis hour +/- 30 minutes). The OBS data for the next 5 hours is not output. How can I get OBSGRID.EXE to create OBS_DOMAIN1* files that contain ALL the available data? I want to nudge every hour, not every 6 hours.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>2. The most recent notes in the <a href="http://www.mmm.ucar.edu/wrf/users/wrfv3.1/How_to_run_obs_fdda.html">WRF User’s Guide</a> make no mention having to concatenate the OBS_DOMAIN1* output from OBSGRID.EXE to OBS_DOMAIN101, but the <a href="http://www.mmm.ucar.edu/wrf/OnLineTutorial/Class/cases/obs_nudging1.php">tutorial notes</a> do say so. Which is correct? Will WRF not read OBS_DOMAIN102, OBS_DOMAIN103, etc.?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>3. If I want to nudge every hour, do I set auxinput11_interval_m = 60 in WRF’s namelist? Or is that supposed to match OBSGRID’s record1 interval ?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>4. If I want to keep nudging till the very end of my simulation, can I set auxinput11_end_h = 99999? <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The meaning of these two values is pretty unclear in the README.namelist, README.obs_fdda, as well as the WRF User’s Guide and tutorial notes. If anyone can shed some light, I’d be most appreciative.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Bart<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div class=MsoNormal align=center style='text-align:center'><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><hr size=2 width="100%" align=center></span></div><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'>This message contains information that may be confidential, privileged or otherwise protected by law from disclosure. 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