FUNCTION eckccf(rt, rs, success)
c------------------------------------------------------------------------
c Calling parameters
c
c  Input:
      REAL*8 rt, rs
c  Output:
      REAL*8 eckccf
      LOGICAL success

c========================================================================
c ECKCCF
c
c  Calculates the cloud correction factor of Tom Eck, given a surface
c  reflectivity rs, and toms reflectivity, rt.
c
c  Reflectivities are given as fractions, not percent.
c
c------------------------------------------------------------------------
c idiot-check rt and rs
c
      IF (rt .LT. 0. .OR. rt .gt. 1.) GOTO 901
      IF (rs .LT. 0. .OR. rs .gt. 1.) GOTO 902

      IF (rt .LT. 0.5) THEN
        eckccf= (1. - rs - rt)/(1. - 2.*rs)
      ELSE
        eckccf= (1. - rt)
      ENDIF

      success=.TRUE.
      RETURN

c-----------------------------------------------------------------------
c Handle error conditions.
c
  901 WRITE(6,91) rt
      GOTO 999
  902 WRITE(6,92) rs
  999 CONTINUE
      success=.FALSE.
      RETURN

   91 FORMAT(' !!! eckccf: calling parameter rt=',f12.2,' out of range.'/
     &       '       value must be in [0,1]')
   92 FORMAT(' !!! eckccf: calling parameter rs=',f12.2,' out of range.'/
     &       '       value must be in [0,1]')
 
      END