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19990422: Data Problems

 > From: Scott Wigginton <address@hidden>
 > Organization: Texas A&M University
 > Keywords: 199904221806.MAA20436 COMET case GRIB Gempak translation

Hi Scott,

Scott Wigginton writes:
 > Good morning,
 > 
 >      Are you folks still having network and server troubles? I just wanted
 > to get an update. I am in need of certain datasets. Also, I am working
 > on CASE10 in your achives. For the model data it says that I can get
 > GRIB or GEMPAK format. Whenever I select Gempak, It sends me GRIB files.
 > How do I obtain the Gempak files which it says are available? I do not
 > know how to convert GRIB files to Gempak, and my class will be in need
 > of Gempka formatted files. Thanks (I need ETA, MRF, AVN, and NGM)

How are you determining that the files you are receiving are GRIB
files?  I just looked at the files for you in the JOSS ftp site and
all the translated ones I checked were GEMPAK files.  One way to check
is to use the octal dump command like this

storm 119% od -c swiggZAA02ztQE | more
0000000   G   E   M   P   A   K       D   A   T   A       M   A   N   A
0000020   G   E   M   E   N   T       F   I   L   E      \0  \0  \0 001
0000040  \0  \0  \0 002  \0  \0 001  \f  \0  \0  \0 001  \0  \0  \0 001
0000060  \0  \0 001 001  \0  \0 003 001  \0  \0 005 334  \0  \0  \0  \n
0000100  \0  \0 001 002  \0  \0 003 003  \0  \0  \0 001  \0  \0   C 201
0000120  \0  \0  \0 201  \0  \0  \0 200  \0  \0   D 001  \0  \0  \0 003
0000140  \0  \0  \0 006  \0  \0  \0 003 377 377 330 361  \0  \0  \0  \0
0000160  \0  \0  \0  \0  \0  \0  \0  \0 306 034   <  \0  \0  \0  \0  \0
0000200  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
*
0001000  \0 003 341 336  \0  \0  \0   >  \0  \0  \0  \0  \0  \0  \0  \0
0001020  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0
*
0002000   G   R   I   D   G   D   T   1   G   T   M   1   G   D   T   2
...

Not very easy to understand but you can see at the top the word GEMPAK 
and the last line I show here GRID.  If they were GRIB files, the
first word would be GRIB.

Another possibility is to run gdinfo on the file like this
storm 120% gdinfo
 GDFILE    Grid file                         $JUNK
 LSTALL    Full list flag                    YES
 OUTPUT    Output device/filename            T
 Parameters requested: GDFILE,LSTALL,OUTPUT.
 GEMPAK-GDINFO>gdfile = $JUNK/swiggZAA02ztQE
 GEMPAK-GDINFO>r

 GRID FILE: $JUNK/swiggZAA02ztQE                                                
    

 GRID NAVIGATION: 
     PROJECTION:          LCC                 
     ANGLES:                25.0   -95.0    25.0
     GRID SIZE:           93  65
     LL CORNER:              12.19   -133.46
     UR CORNER:              57.29    -49.38

 GRID ANALYSIS BLOCK: 
      UNKNOWN ANALYSIS TYPE 

 Number of grids in file:   155

 Maximum number of grids in file:   1500

  NUM       TIME1              TIME2           LEVL1 LEVL2  VCORD PARM
    1     970527/0000F042                       3000  0      HAGL HLCY        
    2     970527/0000F042                         10         HAGL UREL        
    3     970527/0000F042                         10         HAGL VREL        
    4     970527/0000F042                          2         HAGL TMPK        
    5     970527/0000F042                          2         HAGL RELH        
    6     970527/0000F042                          0  10000  SGMA PWTR        
    7     970527/0000F042                       9700  9900   SGMA LIFT        
    8     970527/0000F042                       9700  10000  SGMA TMPK        
    9     970527/0000F042                       9700  10000  SGMA RELH        
   10     970527/0000F042                       9700  10000  SGMA UREL        
...

One problem neither of these methods solves is figuring out what the
files contain.  Since translation in CODIAC changes the filenames,
the information in the name is gone.  You should have received emails
that list which files you ordered and what dataset they were in.  This 
will help you determine the model type.  gdinfo will work to get the
run time and forecast hour.  This can be quite labor intensive for a
lot of files but, at the moment, I don't know of any better method.

Hope this helps.  Let me know if you still have problems.

 > Sincerely,
 > -- 
 >       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 >       @                    Scott B. Wigginton                       @
 >       @ Asistente de Investigaciones - Departamento de Meteorologia @
 >       @                 Universidad de Texas A&M                    @
 >       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 >       @    http://www.met.tamu.edu/personnel/students/swigg2.htm    @
 >       @             E-mail: address@hidden              @
 >       @         Oficina: O&M 1007  Telefono: (409) 845-1680         @
 >       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

Ethan
address@hidden

-- 
Ethan R. Davis                       Telephone: (303) 497-8155
Software Engineer                    Fax:       (303) 497-8690
UCAR Unidata Program Center          E-mail:    address@hidden
P.O. Box 3000
Boulder, CO  80307-3000              http://www.unidata.ucar.edu/