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20031223: sfmod and snmod problems

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  • Subject: 20031223: sfmod and snmod problems
  • Date: Mon, 29 Dec 2003 17:31:20 -0700
Jason,

SFMOD (snmod) are only reading (and transfering) the decoded
data values (SF_RDAT, SN_RDAT calls) and not the 
stored text strings of the raw observations (eg SF_RSTR calls).
So, using SFMOD to transfer METARs will not move the raw observations 
in TEXT and SPCL.

As for file sizes, aside from the raw text portions stored,
then the file sizes may not be the same depending on  missing
stations that might have been added to the original file (using -a
to dcmetr), as well as "COR" corrected reports, where
the data storage in the original file may have been changed
to a smaller value in the COR observation (but that would generally
be a smaller discrepancy than additional stations in the file).

Steve Chiswell.

>From: "Jason Levit" <address@hidden>
>Organization: Storm Prediction Center
>Keywords: 200312232234.hBNMYJp2000006

>
>   Hello,
>
>   I'm having problems with a couple of GEMPAK programs, sfmod and
>snmod.  When I use "sfcfil" and "sncfil" to create a new surface
>observation file, and a new sounding file, and then use "sfmod"
>and "snmod" to dump ALL the data from an original obs or sounding
>file into the new ones...the data file sizes for the new data sets
>are MUCH less than the originals.  I'm using exactly the same
>table files, etc., that are used to decode the data from NOAAPort.
>Shouldn't the file sizes be exactly the same if I'm copying,
>byte-for-byte, the data in the original files into the new?
>
>   Additionally, when I specify sfcfil to create a new file for
>both METAR and TEXT ("METAR|TEXT"), and then copy data from the
>observation file into the new file, the TEXT does not follow
>with it - only the obs.  So, using "sflist", I can see the TEXT
>information in the original decoded obs file...but "sflist" on
>my new file does not reveal any TEXT data.  Is there a reason
>why "sfcmod" will not copy the TEXT data from the original obs
>file in my new one, when I specify it to do so?
>
>   Thanks for any help!
>
>   Jason
>
>-- 
>________________________________________________________________________
>Jason J. Levit                      Techniques Development Meteorologist
>address@hidden           DOC/NOAA/NWS/NCEP Storm Prediction Center
>405/579-0730                                    http://www.spc.noaa.gov/
>