Thunder Road Posted April 26, 2013 Share Posted April 26, 2013 I just want to use GDPLOT2 to get CAPE plotted from a gridded model file. I tried GLEVEL=0 GVCORD=NONE GDPFUN=CAPE which is what my prof told me it was, and that didn't work for the NAM, GFS, or RUC. Then I started Googling and I've tried several different functions but none of those work either. It just keeps saying scalar/vector can't be computed. Anyone have any suggestions? Link to comment Share on other sites More sharing options...
wxmanmitch Posted April 26, 2013 Share Posted April 26, 2013 I found an old GEMPAK script from my meteorology school days that plotted surface based CAPE. Unfortunately, it's been a while since I've played with GEMPAK as I mostly use GrADS nowadays, so I hope it still works. The function that plots CAPE in GEMPAK requires several different arguments, a pressure at a height level, and then the height, dewpoint, and temperature in Celsius at that level. See code snippet below (this was taken from a shell script that invokes and runs GEMPAK): gdplot3 << endgdplot3gdattim=$dategdfile=$fileglevel=nonegvcord=prespanel=0skip=0scale=0gdpfun=cape(pres@2%hght,hght@2%hght,tmpc@2%hght,dwpc@2%hght)type=fcontur=3/5cint=line=fint=100/1000/3200fline=31;30-8clrbar=1/H//0;0/|0.5/2/HWwind=0title=27/-3/~text=1clear=yesdevice=GF|sfccape$time.gif|1000;800proj=lccgarea=41;-77;45;-71map=32filter=yescolors=1reendgdplot3gpend Hope this helps. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 26, 2013 Author Share Posted April 26, 2013 Nah, same error. Although I'm using GDPLOT2, not GDPLOT3: [DG -7] Input grid PRES ^130130/0000F015 @2 %HGHT in CAPE cannot be found. [GDPLOT 2] The requested scalar/vector cannot be computed. I'm beginning to wonder if 211 files are missing something that higher number files have or something. Link to comment Share on other sites More sharing options...
wxmanmitch Posted April 27, 2013 Share Posted April 27, 2013 Nah, same error. Although I'm using GDPLOT2, not GDPLOT3: I'm beginning to wonder if 211 files are missing something that higher number files have or something. Hmm, it worked for me. The code in your original post should've worked too if the grid file you're using has CAPE in it. I think the code I posted is for a grid file that doesn't have CAPE in it, but has those other parameters. Be sure to check that your filename/path with gdfile and time with gdattim are correct. Did you use nagrib to convert the gridded file to a GEMPAK readable format? GEMPAK can't just read a file directly in grib or grib2 format. The other potential issue is that you may be using the wrong grib file and that it doesn't contain the variables you need to calculate and plot CAPE in GEMPAK. You can check to see what variables are in a model grid by viewing the idx (a text file that can be viewed in browser) files associated with each grib file. For today's 18z GFS run you can go to http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.2013042618/ and click on the idx file to see what's in the grid. If you need help interpreting the acronyms, you can look them up here: http://www.nco.ncep.noaa.gov/pmb/products/gfs/ You can also send an email to gembud if you're continuing to have issues: http://www.unidata.ucar.edu/software/gempak/package_information/gembud.html Someone else on here may be able to chime in as well as it's been a little while since I've played with GEMPAK. Link to comment Share on other sites More sharing options...
ohleary Posted April 27, 2013 Share Posted April 27, 2013 Nah, same error. Although I'm using GDPLOT2, not GDPLOT3: I'm beginning to wonder if 211 files are missing something that higher number files have or something. What file(s) are you using? Link to comment Share on other sites More sharing options...
Thunder Road Posted April 28, 2013 Author Share Posted April 28, 2013 What file(s) are you using? http://mtarchive.geol.iastate.edu/2013/01/30/gempak/model/ I've tried with ruc, nam, and avn 211 files of various hours. Link to comment Share on other sites More sharing options...
ohleary Posted April 30, 2013 Share Posted April 30, 2013 http://mtarchive.geol.iastate.edu/2013/01/30/gempak/model/ I've tried with ruc, nam, and avn 211 files of various hours. Not having any issues with any of the NAM or "AVN" files. Here's a sample session...I removed the params that weren't explicitly set to something: GEMPAK-GDPLOT2>l GDFILE = 2013013000_nam212.gem GDATTIM = f018 GLEVEL = 0 GVCORD = none PANEL = 0 SKIP = 0 SCALE = 999 GDPFUN = cape TYPE = C CONTUR = 0 CINT = 0 LINE = 3 FINT = 0 FLINE = 10-20 WIND = BM1 TITLE = 1 TEXT = 1 CLEAR = YES GAREA = 15.0;-131.7;53.0;-61.5 PROJ = MER/0.0;-87.5;0.0 MAP = 1 MSCALE = 0 DEVICE = XW POSN = 0 COLORS = 1 MARKER = 0 GRDLBL = 0 FILTER = YES GEMPAK-GDPLOT2>r Number of times = 1 1 130130/0000F018 PARAMETERS FOR GDPLOT : FRAME NUMBER 1 INITIAL PLOT SETTINGS - GDFILE=2013013000_nam212.gem, GDATTIM=130130/0000F018 GAREA=15.0;-131.7;53.0;-61.5, PROJ=MER/0.0;-87.5;0.0, MAP=1, LATLON= PANEL=0, TITLE=1 OVERLAY TYPE LEVEL VCORD GRID FUNCTION 1 C 0 NONE CAPE Parameters requested: GDFILE,GDATTIM,GLEVEL,GVCORD,PANEL,SKIP,SCALE,GDPFUN, TYPE,CONTUR,CINT,LINE,FINT,FLINE,HILO,HLSYM,CLRBAR,WIND,REFVEC,TITLE,TEXT, CLEAR,GAREA,IJSKIP,PROJ,MAP,MSCALE,LATLON,DEVICE,STNPLT,SATFIL,RADFIL, IMCBAR,LUTFIL,STREAM,POSN,COLORS,MARKER,GRDLBL,FILTER. GEMPAK-GDPLOT2> The (rather ugly) image from the above info is attached. HTH. Link to comment Share on other sites More sharing options...
Thunder Road Posted April 30, 2013 Author Share Posted April 30, 2013 yup I ended up getting it working this afternoon. I didn't really change anything so I don't know why it started working, but... whatever. Thanks for your help. Link to comment Share on other sites More sharing options...
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