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Re: Grib Table Hell

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  • Subject: Re: Grib Table Hell
  • Date: Fri, 09 May 2014 07:55:44 -0600
On 5/9/2014 7:43 AM, HAVENER, KEVIN F GS-12 USAF AFWA 14 WS/WXED wrote:

John,

I've been reading the documentation on netCDF-Java and came across your 
discussion of grib tables.  I am using IDV and Panoply--both of which the 
netCDF_java library, I think--to visualize some AFWA produced grib1 files 
(Center 57, subcenter 2).  Now I've conquered the usage of local tables for 
parameter names (WMO table 2, octet 9).  But AFWA also uses a modified version 
of WMO table 5 (octet 21), adding some time ranges above the defined in the 
defaults 1-124.  Do you have any suggestions on how to feed that data to 
netCDF-Java.  Or at least to get netCDF-Java to ignore time range definitions 
outside the WMO (or NCEP) defaults?  Right now the applications just refuse to 
load the grib files.

To get around this, I ncl_convert2nc and both Panoply and IDV handle the .nc files OK.  
From what I can tell, ncl_convert2nc just munges the parameter name with some information 
it gleans from octet 21. Example: APCP_GDS0_SFC_S133.  This is accumulated precipitation 
for -24 hours to the analysis time according to the AFWA grib documentation and it is 
defined by value 133 in their Table 5.    This is the only occurrence of "133" 
I can find in an ncl_filedump or ncdump of the grib/nc files.

I realize you may not be the person to ask this question of, but maybe you know 
who is the right person.

Kevin Havener, DAFC, 14WS/WXED
Comm 828-271-4323; DSN 673-9044
NIPRNet address@hidden
SIPRNet address@hidden



hi kevin:
ive also seen some table 5 mods from other centers. i will have to look at how i handled that. i think it needs to be coded, so that the correct time coordinate can be derived. ignoring them is also an option i guess.
can you send me an example file, and also a description of what the new time ranges are?
it might also be an opportunity to check if we are using the correct AFWA grib parameter tables, so if you have them we can check. 

john