PROGRAM wmeanf
      PARAMETER(NYEAR=71)
      DIMENSION W(NYEAR,12)
      DIMENSION WMEAN(344,12)
      DIMENSION WCD1(344),WCD2(344), WDIFF(344)
      DIMENSION LALO(344,2)
 
      open(10,form='formatted')
      open(20,form='formatted')

      CALL CRELLW(LALO)

100   FORMAT(10F8.3)
      DO 10 ICD=1,344
         READ(10,100,END=10)W                  !read historical data
         DO 20 MON=7,7                         !for a specific month
            CALL MEAN1(W,MON,ANORM,SD,NYEAR)
            WCD1(ICD)=ANORM                    !get 1961-1970 average
            CALL MEAN2(W,MON,ANORM,SD,NYEAR)
            WCD2(ICD)=ANORM                    !get 1991-2000 average
            WDIFF(ICD)=WCD2(ICD)-WCD1(ICD)
20       CONTINUE
10    CONTINUE

C *** WRITE THE COUNT ON DISK
      CALL WRCD(WCD1,LALO,1.0,21)               !write it out
      CALL WRCD(WCD2,LALO,1.0,22)               !write it out
      CALL WRCD(WDIFF,LALO,1.0,23)               !write it out

      STOP
      END
C
      SUBROUTINE MEAN1(TT,M,ANORM,SD,NYEAR)
      DIMENSION TT(NYEAR,12)
      X=0.
      Y=0.
      IC=0 
c *** for 1961-70
      DO 10 J=31,40
         IC=IC+1
         X=X+TT(J,M)
         Y=Y+TT(J,M)*TT(J,M)
10    CONTINUE
      ANORM=X/10.
      SD=Y/10.-ANORM**2
      SD=SQRT(SD)
      RETURN
      END

      SUBROUTINE MEAN2(TT,M,ANORM,SD,NYEAR)
      DIMENSION TT(NYEAR,12)
      X=0.
      Y=0.
      IC=0
c *** for 1991-00
      DO 10 J=61,70
         IC=IC+1
         X=X+TT(J,M)
         Y=Y+TT(J,M)*TT(J,M)
10    CONTINUE
      ANORM=X/10.
      SD=Y/10.-ANORM**2
      SD=SQRT(SD)
      RETURN
      END