obs_density:

     Observation count by month
     from cray5:/reanl2/bufr/DENC/DENCgrb.yymm
     Note uses GRIB table 140 (see gribtab)

     Downloaded 5/18/98 

     See Bob Kistler for more details

     grib file modified 5/21/98 WNE

     Downloaded 5/18/2001 updates to 03-2001 
       that were calculated by Bob Kister.
       Note: new files already have N-S order
       ctl and idx files updated 5/18/2001



Files:
	gribtab:		wgrib compatible user-defined gribtable
	obs_density.ctl		GrADS control file
	obs_density.idx		GrADS index file
	obs_densityYYYY.grb	grib data file

Comments:
	The data files contain the "platform*time" counts.  For example, each raob 
        sounding will only only be counted once even though it produces U, V, RH, T
	at many levels.  A station that launched 30 sondes in a month would add
	30 to the count.

	The GRIB files use a new NCEP grib table (number 140).  The variables are
	different from the operational and reanalysis tables.  For wgrib to
	use the new table, see ftp://wesley.wwb.noaa.gov/pub/wgrib/usertables.txt.

Revision 7/2019

These files were originally distributed by the development Nomads servers, which also
provided plots.  The files were saved on two independent RAID systems.  Unfortunately
human error error corrupted both RAIDs at the same time.  Fortunately most of the
files were recovered.  (If you find errors in these files, let me know.)


The R1 observation count files use local NCEP grib table 140.  Unfortunately local 
table 140 is now used by the operational models.  How did this happen?  Retirement.

To use the now unofficial NCEP local table 140, you have to recompile wgrib to use the
user-defined parameter table before the official parameter tables.

   gcc -o wgrib -D P_TABLE_FIRST wgrib.c

Then you have to enable the user-defined grib table

sh:     export GRIBTAB=(path)/gribtab
csh     setenv GRIBTAB  (path)/gribtab