Re: [gembud] 0.5 deg GFS GEMPAK files missing data along 0 meridian

• To: "gembud@xxxxxxxxxxxxxxxx" <gembud@xxxxxxxxxxxxxxxx>
• Subject: Re: [gembud] 0.5 deg GFS GEMPAK files missing data along 0 meridian
• From: Robert Mullenax <Robert.Mullenax@xxxxxxxxxxxxx>
• Date: Fri, 20 Feb 2015 14:55:00 +0000

BTW, I have also seen this with FNL analysis data decoded by GEMPAK and ECMWF 
reanalysis files..so it seems to be a GEMPAK issue.
________________________________________
From: gembud-bounces@xxxxxxxxxxxxxxxx [gembud-bounces@xxxxxxxxxxxxxxxx] on 
behalf of Robert Mullenax [Robert.Mullenax@xxxxxxxxxxxxx]
Sent: Friday, February 20, 2015 8:53 AM
To: gembud@xxxxxxxxxxxxxxxx
Subject: [gembud] 0.5 deg GFS GEMPAK files missing data along 0 meridian

I am using gptraj to run some stratospheric balloon forecast trajectories and 
have found that gptraj crashes because of missing data right along the 0 
meridian. The GRIB2 data (GFS 0.5 deg)  was obtained from NOMADS grib filter 
with the following bounding:

leftlon=0 rightlon=360 toplat=90 bottomlat=-90

I decoded the data with dcgrib2, with just dcgrib2 -m 99999 filename

gdinfo says this about the file:

GRID FILE: 2015022000_gfs003.gem

 GRID NAVIGATION:
     PROJECTION:          CED
     ANGLES:                 0.0     0.0     0.0
     GRID SIZE:          720 361
     LL CORNER:             -90.00      0.00
     UR CORNER:              90.00     -0.50

 GRID ANALYSIS BLOCK:
      UNKNOWN ANALYSIS TYPE

 Number of grids in file:  1924

I have no data at 0:

 GEMPAK-GDPOINT>r

GDFILE: 2015022000_gfs003.gem
GPOINT: -45;0
GVCORD: pres
GLEVEL: 7
GFUNC : urel
SCALE : 0
     150220/0000F012 :  -9999.00000

I do have data at 0.1 and -0.1

GDFILE: 2015022000_gfs003.gem
GPOINT: -45;0.1
GVCORD: pres
GLEVEL: 7
GFUNC : urel
SCALE : 0
     150220/0000F012 :     -5.82000
 Parameters requested: GDATTIM,GDFILE,GLEVEL,GPOINT,GVCORD,GFUNC,SCALE.
 GEMPAK-GDPOINT>gpoint=-45;-0.1
 GEMPAK-GDPOINT>r

GDFILE: 2015022000_gfs003.gem
GPOINT: -45;-0.1
GVCORD: pres
GLEVEL: 7
GFUNC : urel
SCALE : 0
     150220/0000F012 :     -5.80000
 Parameters requested: GDATTIM,GDFILE,GLEVEL,GPOINT,GVCORD,GFUNC,SCALE.
 GEMPAK-GDPOINT>

I am assuming the issue is with the decoding of the file, but I am at a loss to 
figure out how to fix that. Any ideas?

Thanks,
Robert Mullenax
CSBF Meteorology



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• References:
  • [gembud] 0.5 deg GFS GEMPAK files missing data along 0 meridian
    • From: Robert Mullenax