[GEMPAK #UER-356689]: NAGRIB not decoding AMPS WRF grids

> For future reference how did you initially determine what the grdarea was for 
> the UV grid?
> 
> 
Robert,

As I recall, I created a wmogrib2.tbl file with just UREL and VREL (33 and 34)
so that those would be the only parameters decoded. You could just keep 2 
different wmogrib2.tbl
versions aand link the appropriate in the directory before running nagrib or 
dcgrib2.
If you did that, you could just use the CPYFIL=gds and not have to set the 
PROJ, KXKY and GRDAREA.

Steve Chiswell
Unidata User Support




> 
> 
> -----Original Message-----
> From: Unidata GEMPAK Support [mailto:address@hidden]
> Sent: Tue 12/11/2007 2:11 PM
> To: Robert Mullenax
> Cc: address@hidden
> Subject: [GEMPAK #UER-356689]: NAGRIB not decoding AMPS WRF grids
> 
> Robert,
> 
> When I use your settings for uv, I decode the winds as expected.
> 
> 
> 
> 4370 GRIB messages were read or scanned from the GRIB file:
> 2007120300_D5.grb
> 
> 868 grids were written to the GEMPAK file:
> antarctica_uv.gem
> 
> 
> When I use your grdarea for the antarctica.gem file,
> GRDAREA = -78.34;156.78;-75.77;174.52
> I get the 0 grids decoded as you saw. I notice that the longitudes for LL and 
> UR has changed
> slightly by .01 each when running dcgrib2 on the data.
> 
> When I change this in nagrib to:
> PROJ     = str/-90;180;0
> GRDAREA  = -78.34;156.77;-75.77;174.51
> KXKY     = 159;171
> 
> I get:
> 4370 GRIB messages were read or scanned from the GRIB file:
> 2007120300_D5.grb
> 
> 1890 grids were written to the GEMPAK file:
> antarctica.gem
> 
> I haven't looked in to the source of the .01 difference, but since the LL 
> point
> is from the data itself, I assume that the post-processing involved in 
> converting from the model
> domain to grib is just that much different in roundoff error than previous.
> 
> So, to fix your decoding, you will have to modify the GRDAREA value.
> 
> The other unknown parameters of numbers greater than 127 will be referenced
> in ncargrib2.tbl, and if you happen to know those parameters, you can create a
> table so that they are decoded as well.
> 
> Steve Chiswell
> Unidata User Support
> 
> 
> 
> 
> 
> 
> >
> > Steve,
> >
> > Last year you helped me write NAGRIB scripts that would handle the AMPS MM5 
> > and WRF grids.  The GRIB files provided by AMPS have the U/V winds offset 
> > by one grid point.  Decoding with dcgrib2 will allow  you to display 
> > everything but winds fine.  Winds either display in the wrong place or 
> > won't display at all (and causes gdplot2 to dump core).  The solution was 
> > to decode the grib messages with nagrib2 and set the proper geog for the 
> > U/V, then decode the rest then merge back together:
> >
> > #!/bin/csh
> > set DATE=`date +%Y%m%d`
> > #set DATE=20061106
> > set HR=$1
> > source ~gempak/GEMPAK/Gemenviron
> > nagrib << EOF
> > GBFILE   = /data/ldm/EXP/mm5/${DATE}${HR}_D5.grb
> > INDXFL   =
> > GDOUTF   = /usr2/config/grdtmp/mm5d5/antarctica_uv.gem
> > PROJ     = str/-90;180;0
> > GRDAREA  = -78.34300;156.7770;-75.74857;174.6063
> > KXKY     = 160;172
> > MAXGRD   = 10000
> > CPYFIL   =
> > GAREA    = dset
> > OUTPUT   = t
> > GBTBLS   =
> > GBDIAG   =
> > PDSEXT   = NO
> > OVERWR   = NO
> > r
> >
> > e
> > EOF
> > gpend
> > nagrib << EOF2
> > GBFILE   = /data/ldm/EXP/mm5/${DATE}${HR}_D5.grb
> > INDXFL   =
> > GDOUTF   = /usr2/config/grdtmp/mm5d5/antarctica.gem
> > PROJ     = str/-90;180;0
> > GRDAREA  = -78.34;156.78;-75.77;174.52
> > KXKY     = 159;171
> > MAXGRD   = 10000
> > CPYFIL   =
> > GAREA    = dset
> > OUTPUT   = t
> > GBTBLS   =
> > GBDIAG   =
> > PDSEXT   = NO
> > OVERWR   = NO
> > r
> >
> > e
> > EOF2
> > gpend
> > cd /usr2/config/grdtmp/mm5d5/
> > /usr2/config/scripts/gempak/antarctica_merge.csh
> > cleanup
> > mv antarctica.gem /data/ldm/gempak/model/mm5_ice/${DATE}${HR}_d5.gem
> > rm antarctica_uv.gem
> >
> >
> > where the merge script is:
> > /usr2/config/scripts/gempak% more ant*merge.csh
> > #!/bin/csh -f
> >
> >
> > @ SHOUR=6
> > @ EHOUR=36
> >
> > set LEVELS=("1000" "925" "850" "700" "600" "500" "400" "300" "250" "200" 
> > "150" "100" "10" "300")
> > while ( $SHOUR <= $EHOUR )
> >
> > if ( $SHOUR < 10 ) then
> > set FHOUR=F00${SHOUR}
> > else
> > set FHOUR=F0${SHOUR}
> > endif
> >
> > @ LCNT=1
> >
> > foreach LEVEL ($LEVELS)
> > if ( $LCNT < 13 ) then
> > set GVCORD="PRES"
> > else
> > set GVCORD="HGHT"
> > endif
> >
> > echo LEVEL $LEVEL $GVCORD
> >
> >
> > gddiag<< EOF_GDDIAG
> > GDFILE   = antarctica_uv.gem
> > GDOUTF   = antarctica.gem
> > GFUNC    = UREL
> > GDATTIM  = $FHOUR
> > GLEVEL   = $LEVEL
> > GVCORD   = $GVCORD
> > GRDNAM   =
> > GRDTYP   = S
> > GPACK    = none
> > GRDHDR   =
> > PROJ     =
> > GRDAREA  =
> > KXKY     =
> > MAXGRD   =
> > CPYFIL   =
> > ANLYSS   =
> > run
> >
> > GFUNC    = VREL
> > run
> >
> > exit
> > EOF_GDDIAG
> > @ LCNT = $LCNT + 1
> > end
> >
> > @ SHOUR = $SHOUR + 1
> > end
> > gpend
> >
> > exit 0
> >
> >
> > This is and has been working fine for the MM5.  However, the WRF decoding 
> > does not work after I turned it back on this week.  All the AMPS guys are 
> > on the ice right now so it's difficult to ask if they have changed 
> > anything.  I do not believe they have.  It seems like it MAY be a problem 
> > with nagrib.  The reason I say that is that I can decode the file properly 
> > with dcgrib2, and can display anything other than winds.  Winds as always 
> > won't display and gdplot2 core dumps.  When the nagrib script runs it 
> > seemingly finds nothing to decode.  See below:
> >
> >
> > [NAGRIB 3]  No valid parameter found for 170.
> > [NAGRIB 3]  No valid parameter found for 171.
> > [NAGRIB 3]  No valid parameter found for 153.
> > [NAGRIB 3]  No valid parameter found for 178.
> > [NAGRIB 3]  No valid parameter found for 170.
> > [NAGRIB 3]  No valid parameter found for 171.
> > [NAGRIB 3]  No valid parameter found for 153.
> > [NAGRIB 3]  No valid parameter found for 178.
> > [NAGRIB 3]  No valid parameter found for 170.
> > [NAGRIB 3]  No valid parameter found for 171.
> > [NAGRIB 3]  No valid parameter found for 153.
> > [NAGRIB 3]  No valid parameter found for 178.
> > [NAGRIB 3]  No valid parameter found for 170.
> > [NAGRIB 3]  No valid parameter found for 171.
> > [NAGRIB 3]  No valid parameter found for 153.
> > [NAGRIB 3]  No valid parameter found for 178.
> > [NAGRIB 3]  No valid parameter found for 170.
> > etc..etc..etc..
> >
> >
> > 4368 GRIB messages were read or scanned from the GRIB file:
> > 2007120112_D5.grb
> >
> > 0 grids were written to the GEMPAK file:
> > tr.gem
> >
> >
> > GRID FILE: tr.gem
> >
> > GRID NAVIGATION:
> > PROJECTION:          STR
> > ANGLES:               -90.0   180.0     0.0
> > GRID SIZE:          160 172
> > LL CORNER:             -78.35    156.77
> > UR CORNER:             -75.75    174.61
> >
> > GRID ANALYSIS BLOCK:
> > ANALYSIS TYPE:        BARNES
> > DELTAN:               4.000
> > DELTAX:           -9999.000
> > DELTAY:           -9999.000
> > GRID AREA:           -80.00  156.00  -74.00  176.00
> > EXTEND AREA:         -80.00  156.00  -74.00  176.00
> > DATA AREA:           -80.00  156.00  -74.00  176.00
> >
> > Number of grids in file:     0
> >
> > Maximum number of grids in file:  10000
> >
> > First time in file: ^L\233^G^Hp/
> > ^Hh/
> > ^Hl/
> > ^Hd/
> > ^H^V\307        ^H\200
> > Last  time in file: \200
> >
> >
> >
> > You can grab a file of the GRIB data to test with from:
> >
> > http://psnwx.balloonfacility.org/csbf/2007120300_D5.grb
> >
> > username is csbfmet, password is p!bal.
> >
> > Thanks a bunch,
> > Robert Mullenax
> > CSBF Meteorology
> >
> >
> >
> >
> 
> 
> Ticket Details
> ===================
> Ticket ID: UER-356689
> Department: Support GEMPAK
> Priority: Normal
> Status: Closed
> 
> 
> 
> 


Ticket Details
===================
Ticket ID: UER-356689
Department: Support GEMPAK
Priority: Normal
Status: Closed