C$$$  MAIN PROGRAM DOCUMENTATION BLOCK
C
C MAIN PROGRAM: GR2RR2       MAKE 3-HOUR PREPBUFR FILE FROM 6-HOUR PREPBUFR FILE
C   PRGMMR: ROGERS           ORG: NP22        DATE: 97-12-30  
C
C ABSTRACT: GLOBAL MODEL USE 6 HOUR PREPBUFR FILE.
C   REMOVES SATEMP DATA.
C   REMOVES SATWND MASS DATA.
C   REMOVES DATA OUTSIDE THE REGIONAL DOMAIN.
C   T->TV
C
C PROGRAM HISTORY LOG:
C   ??-??-??  ??
C
C USAGE:
C
C   echo "YYYYMMDDHH" | narr_grtorr2.x
C
C   INPUT FILES:
C     UNIT20     - PREPBUFR FILE
C
C   OUTPUT FILES:
C     UNIT51     - PREPBUFR FILE
C
C
C   SUBPROGRAMS CALLED:
C     OPENBF
C     IREADMG
C     UFBINT
C     UFBCPY
C     WRITESB
C     MOIFUN (INTERNAL)
C
C   EXIT STATES:
C     COND =   0 - SUCCESSFUL RUN
C
C   REMARKS:
C
C ATTRIBUTES:
C   LANGUAGE: STANDARD FORTRAN 90
C
C$$$