[gembud] Nagrib2 not fully degribbing CFS2 grib2 files

• To: gembud@xxxxxxxxxxxxxxxx
• Subject: [gembud] Nagrib2 not fully degribbing CFS2 grib2 files
• From: pmanousos@xxxxxxxxxxxxxxxxxxx
• Date: Thu, 9 Jun 2011 09:30:37 -0400

Hi.  We are attempting to use NCEPs CFSV2 (Climate Forecast System Ver 2) 
data using NAWIPS 6.2.0 and have come to a hurdle that has not been 
specifically documented in the GEMBUD archives -- nagrib2 at best only 
partially degribs the CFS2 grib2 files.  We are trying to degrib these 
files into a gempak grid in order to use gdpoint to extract values from 
the grid at sites of interest. 

Here are some details of the data and the issues noted:

CFS2 files in grib2 format are found at 
http://cfs.ncep.noaa.gov/pub/raid0/cfsv2/verification/monthly/ 
Depending the grib2 file pulled from this site, nagrib2 either does not 
degrib the file or only partially degribs the file into a gempak grid
wgrib2 -v <filename> does show the file contains data

A contact within NCEP duplicated the results we are seeing but is also not 
certain of the cause.  We loosely suspect a combination of the CFSV2 files 
being on a gaussian grid (although if that were the case, then we shouldnt 
be getting any grid file at all -- and we are) and/or a need to create a 
local grid table for nagrib2 to reference since these may be specialized 
fields not contained in $GEMTBL/grid.  We also are not certain the goofy 
"missing=0" portions of the grib message is leading to a nagrib "failure".

Any one know the cause of this, and more importantly a possible work 
around?  If you need more details, see below.
==============================================

1. Pulled 
http://cfs.ncep.noaa.gov/pub/raid0/cfsv2/verification/monthly/flxl06/flxl06.gdas.200912.grb2
 
and then ran it through nagrib2 as follows:

GBFILE=flxl06.gdas.200912.grb2
GDOUTF=t.grd
PROJ=
GRDAREA=
KXKY=
MAXGRD=
CPYFIL=GDS
GAREA=
OUTPUT=T
G2TBLS=
G2DIAG=
OVERWR=no
PDSEXT=no

2. After running and gpending we do NOT get the grid file "t.grd". Instead 
we get a message 
"1 GRIB messages were read or scanned from the GRIB file: 
flxl06.gdas.200912.grb" and 
"0 grid were written to the GEMPAK file: t2.grd". 

3. "wrgrib2 -v flxl06.gdas.200912.grb" contains 104 grib messages (and a 
line count of 106 using | wc -l of 106).. but each line or message has 
curious listings.  Here is just one of the lines resulting from this 
wgrib2 listing 
37:2922365:d=2009120100:TMP Temperature [K]:2 m above ground:124 hour 
???@6 hour(6-6 hour ??? fcst),missing 0:

4. cat $GEMTBL/grid/*grib2* | grep TMP | grep TMPK | sort | uniq   yields
011 Temperature K TMPK 0 -9999.00 0 0
025 Temperature anomaly K TMPKA 0 -9999.00 0 0
080 Water Temperature K WTMPK 0 -9999.00 0 0

5. Similarly 
http://cfs.ncep.noaa.gov/pub/raid0/cfsv2/verification/monthly/pgbanl/pgbanl.gdas.200404.grb2
 
run through nagrib2 only partially degribs the file and creates a "t.grd" 
grid file -- but of the 522 messages in the grib file only 52 were written 
to t.grd (example -- none of the hght fields were written to the grid file 
t.grd). 

6. "wrgrib2 -v pgbanl.gas.200404.grb2 | grep HGT" does list a number of 
height fields available.. but they all have some similar curious listings. 
 Here is just one of the lines resulting from this wgrib2 listing..
186:11109623:d=2004040100:HGT Geopotential Height [gpm]:500 mb:21@6 hour 
???(0-6 hour ave fcst),missing=0:

7. cat $GEMTTBL/grid/* | grep HGT | grep -v "CLD TOP" | grep -v "CIG HGT" 
| grep -v "ANTENNA" | grep -v "LOOP CORRECTION" reveals nothing.


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