Table 8.a   Reason codes associated with step "PREPRO", 
            program code 001 (last revised 5/30/2001). 

NOTE 1: 
FOR ALL DATA TYPES EXCEPT TOVS AND GOES RETRIEVALS, THE ENCODED 
QUALITY MARKER FOR SPECIFIC HUMIDITY (QQM) IS SET 
TO THE ENCODED QUALITY MARKER FOR TEMPERATURE (TQM).
THEREFORE, ANY EVENTS ON TQM FOR THESE DATA TYPES ARE ALSO EVENTS ON QQM. 
THE EVENTS ON QQM LISTED HERE ARE SEPARATE FROM THOSE ON TQM. 

NOTE 2: 
FOR ALL DATA TYPES, THE ENCODED QUALITY MARKER FOR WIND U- AND 
V-COMPONENTS (WQM) IS ALSO THE ENCODED QUALITY MARKER 
FOR WIND SPEED AND DIRECTION (DFQ) AND FOR WIND
SPEED (SQM). IN ADDITION, ALL ENCODED EVENTS FOR THE UOB,
VOB,WQM SEQUENCE ALSO APPLY TO THE DDO,FFO,DFQ SEQUENCE. 
  

KEY: 
IN "R.CODE" COLUMN: 
               B - OCCURS IN ALL OPERATIONAL VERSIONS OF PREPRO. 
               N - CURRENTLY DOES NOT OCCUR IN ANY OPERATIONAL VERSION OF PREPRO. 

IN "MNEMONIC" COLUMN: 
               ## - QUALITY MARKER IS USUALLY DEFINED AS THE WORSE OF THE TWO 
                    SPANNING LEVEL QUALITY MARKERS FOR THE DATA USED TO CREATE 
                    THE OBSERVATION (OF THE SAME DATA TYPE).
               @@ - QUALITY MARKER IS USUALLY DEFINED AS THE WORSE OF THE PAIR 
                    OF HEIGHT AND TEMPERATURE QUALITY MARKERS ON THE TWO SPANNING 
                    LEVELS FOR THE DATA USED TO CREATE THE OBSERVATION.
               ** - OBSERVATION OR QUALITY MARKER IS OBTAINED AS DEFINED IN EVENT MEANING. 
  

 R.CODE                MEANING                                            MNEMONICS AFFECTED AND NEW VALUE
                                                                          FOR OBS, Q.M.
========           =================================================      ================================ 
 100 B             OBSERVATION AND QUALITY MARKER ON REPORT LEVEL 
                   UNCHANGED FROM ORIGINAL VALUES READ INTO PROGRAM 
                   PREPDATA.

(EVENTS # 101-129 PERTAIN TO DATA OBSERVATIONS AND QUALITY MARKERS THAT ARE GENERATED BY PREPRO. 
 DATA OBSERVATIONS WERE MISSING PRIOR TO PREPRO.)

 101 N             OBSERVATION ON UPPER-AIR CATEGORY 4 (WINDS-BY-          PRC-> POB= **,PQM= ##
                   HEIGHT) LEVEL CREATED VIA LINEAR AVERAGING OF           ZRC-> ZOB= **,ZQM= ## 
                   REPORTED DATA ON SPANNONG LEVELS.                       TRC-> TOB= **,TQM= ##

 102 N             OBSERVATION ON UPPER-AIR REPORT LEVEL CREATED           TRC-> TOB= **,TQM= ## 
                   VIA LINEAR LOG-P INTERPOLATION OF REPORTED DATA         WRC-> UOB,VOB= **,WQM= ##
                   ON SPANNING LEVELS.

 103 B(PRC)        OBSERVATION ON UPPER-AIR REPORT LEVEL CREATED           PRC-> POB= **,PQM= ## 
     N(ZRC,TRC)    VIA HYDROSTATIC INTEGRATION OF REPORTED DATA            ZRC-> ZOB= **,ZQM= @@ 
                   ON SPANNING LEVELS. {PRC AFFECTED ONLY FOR              TRC-> TOB= **,TQM= ## 
                   CATEGORY 4 (WINDS-BY-HEIGHT) LEVELS.}

 105 N             NEW REPORT PRESSURE LEVEL CREATED. PRESSURE             PRC-> POB= **,PQM= 2 
                   OBSERVATION CONSIDERED TO BE OF NEUTRAL QUALITY. 
                   {FOR SSM/I WIND SPEED AND ERS AND QUIKSCAT 
                   SCATTEROMETER WIND REPORTS, PRESSURE OBSERVATION 
                   IS ASSIGNED THE VALUE OF 1013 MB (LOGIC IS
                   CURRENTLY NOT IN PLACE TO ASSIGN REASON CODE 
                   FOR THIS EVENT). OTHERWISE, PRESSURE OBSERVATION 
                   IS ASSIGNED TO THE SPECIAL "CATEGORY 7" 25 OR 50 
                   MB PRESSURE LEVELS ONTO WHICH OBSERVATIONS ARE 
                   INTERPOLATED FOR UPPER-AIR REPORTS
                   (REGIONAL VERSION ONLY).}

 116 B             PRESSURE CALCULATED FROM REPORTED ALTITUDE VIA          PRC-> POB= **,PQM= 2  
                   U.S. STANDARD ATMOSPHERE. CATEGORY 6 (SINGLE-
                   LEVEL AIRCRAFT/SATWND/ RECCO) LEVEL OR CATEGORY 4
                   (WINDS-BY-HEIGHT) UPPER-AIR LEVEL FOR REPORT 
                   WITH NO VALID HEIGHT LEVELS.  CALCULATED PRESSURE  
                   OBSERVATION IS CONSIDERED TO BE OF NEUTRAL QUALITY.
======================================================================================================

Most PREPRO "events" are not yet assigned a reason code, so it is missing. In this case the 
observation and/or quality marker may or may not be the original value. (This will change 
in the future as events and their reason codes are added to the PREPRO step.)