November 15, 1999

MEMORANDUM TO:  Record
FROM:           Dennis A. Keyser -- NP22
Subject:        Changes to CRAY Data Preprocessor (PREPDATA)
                (September 21, 1998 Version -- UPDATE # 5)

The September 21, 1998 CRAY version of the data preprocessor
program (PREPDATA) was updated for the fifth time.  UPDATE #5 was
implemented on 1200 UTC 09 November 1999.  Except where noted,
the changes below affect all four versions: 3DVAR, OI, SSI, and
RUC.

**************** C R A Y   U P D A T E   # 5  *******************

I.  GENERAL CHANGES

     1) When the existing data card switches are set-up to
exclude a particular BUFR type and subtype, the program now looks
for BUFR messages in the input dump files that have Table A
entries defining the BUFR type and subtype.  Such messages are
now skipped over without decoding any reports. This makes the
program more efficient than before, when reports that were not
processed into the PREPBUFR file were still decoded from the
input dump files.  (This currently applies only to upper-air and
surface data types read in via subroutine IW3UNPBF). [MAIN, PREP,
SFCDTA, IW3UNPBF]



II. OPERATIONAL CHANGES SPECIFIC TO A DATA TYPE


  A. CHANGES TO SURFACE DATA PROCESSING

     1) Namelist switches FWINDO, SFMASS, and SFWIND can now
differentiate between surface land synoptic and surface land
METAR reports. [MAIN, SFCDTA]

     2) SSI version only: In response to C90 fire on 9/27/1999,
data card changes turned off the processing of the METAR data
(the METAR data had been turned off in the AVN/SSI since
approximately 10/5/1999 via a temporary change in the AVN
"adpsfc" data dump to exclude the METAR data.  This
implementation turns the METAR processing off in the FNL as
well).  








  B.  CHANGES TO UPPER-AIR (RAOB, PIBAL, PROFILER, VADWND) DATA   
      PROCESSING
     
     1) In the processing of category 4 (winds-by-height) levels,
a manual (SDM) keep flag on a wind observation is now honored. 
Prior to this, all wind quality marks on category 4 levels were
set to at best (lowest) 2 (default).  This is still the case for
winds originally containing a good (1) quality marker. [MAIN,
WNDBYZ]

     2) For RAOBS and PIBALS only: All input tropopause levels
are processed into the PREPBUFR file with a singular category of
5.  Prior to this, tropopause levels were processed as both
category 3 and 5 (like the old Office Note 29).  This change will
allow users of the PREPBUFR file to better define the tropopause
levels. [IW3UNPBF]

     3) For RAOBS and PIBALS only: All mandatory levels
containing only wind information (no mass data) are now processed
into the PREPBUFR file with a category of 1.  Prior to this,
these levels were processed as category 3 (like the old Office
Note 29). [IW3UNPBF]

     4) For RAOBS and PIBALS only: All variables on duplicate
pressure levels (for category 2 and 3) or on duplicate height
levels (for category 4) [as read in from the report in the BUFR
data dump] are now flagged with a quality mark of 14 when one or
more of the non-vertical coordinate data are different.  Prior to
this, both levels were processed into the PREPBUFR file.  The
idea is that if the two levels disagree it is better to throw
them both out than to retain any bad data. [IW3UNPBF]


  C.  CHANGES TO SATELLITE WIND DATA PROCESSING

     1) SSI version only: In response to C90 fire on 9/27/1999,
data card changes turned off the processing of Indian IR and
visible satwinds (done approximately 10/5/1999).  (Note: Reports
were flagged anyway.)

     2) SSI and 3DVAR versions only: In response to C90 fire on
9/27/1999, data card changes turned off the processing of NESDIS
high-density visible satwinds (done approximately 10/5/1999 in
SSI and done with this implementation in 3DVAR). (Note: Reports
were flagged by all versions anyway.) 


  D.  CHANGES TO VAD WIND DATA PROCESSING
     
     1) SSI and 3DVAR versions only: In response to C90 fire on
9/27/1999, data card changes turned off the processing of these
data (done approximately 10/5/1999 in SSI and done with this
implementation in 3DVAR). (Note: Reports were flagged by all
versions anyway.)

  E.  CHANGES TO SSM/I DATA PROCESSING

     1) SSI version only: In response to C90 fire on 9/27/1999,
data card changes turned off the processing of SSM/I wind speed
and total precipitable water (done approximately 10/5/1999). 
(Note: SSM/I precipitable water reports were flagged anyway.)
(A subsequent change, implemented 12Z 07 December 1999, turned
off the processing of SSM/I wind speed and TPW in the 3dvar
version]


  F.  CHANGES TO ERS DATA PROCESSING

     1) SSI version only: In response to C90 fire on 9/27/1999,
data card changes turned off the processing of ERS wind (done
approximately 10/5/1999).