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19990131: hemispheric grids in GEMPAK/GARP

Gary,

I am looking at the 500mb heights and surface pressure grids 
from the avn thinned grids in both gdcntr and Garp 2.01 and don't
see any line breaks in the contour field around 30W which is the
wrap point for the thinned grids. The thinned grids are in 8
pieces and get stitched together in the gempak grid file by dcgrib.
I also looked at the f084 500mb height for the MRF and that looks OK to.

If you can post a few gifs, that would help me see what you are looking at.
I may need to look at the same grid file you are looking at too.
If you can post that to ~gbuddy/incoming that might be useful.

Steve Chiswell
Unidata User Support

>From: address@hidden (Gary Lackmann)
>Organization: .
>Keywords: 199902012039.NAA11198

>> 
>> Gary,
>> 
>> The wrapping point for the AVN thinned grids (eg 1.25x.125 degree grids is
>> 30W, not near the Greenwhich meridian. This is the global AVN data set.
>> 
>> Is this the AVN data set you are refering too?
>> 
>> Can you provide me with the program input and file data type you are using
>> where you see this behavior?
>> 
>> Thanks,
>> 
>> Steve Chiswell
>> ****************************************************************************
>> Unidata User Support                                    UCAR Unidata Program
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>> 
>Hi Steve,
>
>The decoder program is dcgrib and the file type is gempak.  Both the
>MRF and AVN_thin grids exhibit this behavior when viewed using GARP.
>The MRF breaks at the meridian, and the AVN is broken at 30W.  If you
>like, I can save a few example gifs out of garp and post them on our
>web page, or for ftp.  Also, I could place an example grid file in the
>anonymous ftp directory if that would help.
>
>The pattern-action we use for the MRF is shown below:
>
>HRS     ^H[HPUV][EF][A-Z][0-9][0-9] KWB. ([0-3][0-9])([0-2][0-9])..
>        PIPE    /weather/ldm/gempak/NAWIPS/bin/sol/dcgrib
>                -d data/gempak/logs/dcgrib.log
>                -g /weather/ldm/gempak/NAWIPS/gempak5.4/tables
>                PACK data/gempak/hds/YYMMDDHH_mrf.gem
>
>The AVN exhibits the same behavior (except breaks at 30 instead
>of the Greenwich meridian) when viewed in GARP.
>
>HRS     ^H.[I-P]... KWB. ([0-3][0-9])([0-2][0-9]).*
>        PIPE    /weather/ldm/gempak/NAWIPS/bin/sol/dcgrib
>                -d data/gempak/logs/dcgrib.log
>                -g /weather/ldm/gempak/NAWIPS/gempak5.4/tables
>                -q"lin,dlat=2.5,dlon=2.5"
>                PACK data/gempak/hds/YYMMDDHH_thin.gem
>
>