*DECK UTILS
C
      SUBROUTINE SIGTOZ(ZZ,H,T,TLEV,ZLEV,FSM,IM,JM,KB)
C-------------------------------------------------------------------
C     THIS ROUTINE LINERLY INTERPOLATES TLEV AT THE LEVEL,
C     ZLEV, FROM T LOCATED ON SIGMA LEVELS, ZZ.
C     ZLEV AND ZZ ARE NEGATIVE QUANTITIES.
C     A SEARCH IS MADE TO FIND ZZ(K)*H AND ZZ(K+1)*H WHICH
C     BRACKETS ZLEV; THEN THE INTERPOLATION IS MADE.
C     IN THE REGION < 0 and > ZZ(1) AND,  IN THE REGION,
C     < ZZ(KB-1) and > -1, DATA IS EXTRAPOLATED.
C     NOTE THAT A NEW MASK ,FSM, IS CREATED.
C
C     THE VALUES OF H SUPPLIED TO THIS SUBROUTINE SHOULD BE
C     APPROPRIATE TO THE VARIABLE T. FOR EXAMPLE, IF T IS THE
C     X-COMPONENT OF VELOCITY, H SHOULD THE AVERAGE OF DEPTH
C     AT I AND I-1.
C-------------------------------------------------------------------
      DIMENSION ZZ(KB),H(IM,JM),T(IM,JM,KB),TLEV(IM,JM),FSM(IM,JM)
      TLEV=0.
      FSM=0.
C
      DO 200 J=2,JM-1 
      DO 200 I=2,IM-1
      IF(ZLEV.GT.ZZ(1)*H(I,J)) THEN
            K=1
            TLEV(I,J)=T(I,J,K)+(ZLEV-ZZ(K)*H(I,J))
     1         *(T(I,J,K+1)-T(I,J,K))/((ZZ(K+1)-ZZ(K))*H(I,J))
            GO TO 200
            FSM(I,J)=1.
      ENDIF
      K=1
  100 CONTINUE
C
C
      IF(ZLEV.LE.(ZZ(K)*H(I,J)).AND.ZLEV.GE.(ZZ(K+1)*H(I,J))) THEN
              TLEV(I,J)=T(I,J,K)+(ZLEV-ZZ(K)*H(I,J))
     1           *(T(I,J,K+1)-T(I,J,K))/((ZZ(K+1)-ZZ(K))*H(I,J))
              FSM(I,J)=1.
              GO TO 200
      ELSE
              K=K+1
              IF(K.LT.(KB-1)) GO TO 100
      ENDIF
      IF(ZLEV.LE.(ZZ(K)*H(I,J)).AND.ZLEV.GE.(-H(I,J))) THEN
                 TLEV(I,J)=T(I,J,K-1)+(ZLEV-ZZ(K-1)*H(I,J))
     1             *(T(I,J,K)-T(I,J,K-1))/((ZZ(K)-ZZ(K-1))*H(I,J))
                 FSM(I,J)=1.
      ENDIF
  200 CONTINUE
      RETURN
      END
C
      SUBROUTINE SMOOTH(A,B,FSM,IM,JM,NITS)
C-------------------------------------------------------------------
C     THIS ROUTINE SMOOTHS DATA WITH A FIVE POINT LAPLACIAN FILTER.
C-------------------------------------------------------------------
C  A is the array to be smoothed.
C  B is work space that must be provided through the arguement list.
C  FSM=1 if element is to include in the smoothing operator. Otherwise, FSM=0.
C  NITS is the number of smoothing operations.
C
      DIMENSION A(IM,JM),B(IM,JM),FSM(IM,JM)
      DO 100 N=1,NITS
      DO 200 J=2,JM-1
      DO 200 I=2,IM-1
      SMFAC=FSM(I+1,J)+FSM(I,J-1)+FSM(I-1,J)+FSM(I,J+1)+1.S-5
      B(I,J)=A(I,J)+(.5S0/SMFAC)
     1               *(A(I+1,J)*FSM(I+1,J)+A(I,J-1)*FSM(I,J-1)
     2                +A(I-1,J)*FSM(I-1,J)+A(I,J+1)*FSM(I,J+1)
     3                -SMFAC*A(I,J))
  200 CONTINUE
      DO 210 J=1,JM,JM-1
      DO 210 I=2,IM-1
      SMFAC=FSM(I+1,J)+FSM(I-1,J)+1.S-5
      B(I,J)=A(I,J)+(.5S0/SMFAC)
     1               *(A(I+1,J)*FSM(I+1,J)
     2                +A(I-1,J)*FSM(I-1,J)
     3                -SMFAC*A(I,J))
  210 CONTINUE
      DO 220 J=2,JM-1
      DO 220 I=1,IM,IM-1
      SMFAC=FSM(I,J-1)+FSM(I,J+1)+1.S-5
      B(I,J)=A(I,J)+(.5S0/SMFAC)
     1               *(A(I,J-1)*FSM(I,J-1)
     2                +A(I,J+1)*FSM(I,J+1)
     3                -SMFAC*A(I,J))
  220 CONTINUE
      A=B*FSM
  100 CONTINUE
      RETURN
      END
*DECK SINTER       
      SUBROUTINE SINTER(X,A,Y,B,M,N)   
C        
C        A SPECIAL CASE OF INTERP ....NO EXTRAPOLATION BELOW DATA    
C        THIS ROUTINE LINEARLY INTERPOLATES AND EXTRAPOLATES AN ARRAY B        
C        X(M) MUST BE DESCENDING       
C        A(X) GIVEN FUNCTION 
C        B(Y) FOUND BY LINEAR INTERPOLATION AND EXTRAPOLATION        
C        Y(N) THE DESIRED DEPTHS       
C        M    THE NUMBER OF POINTS IN X AND A    
C        N    THE NUMBER OF POINTS IN Y AND B    
C        
      HALF PRECISION X(M),A(M),Y(N),B(N)
C        
C        EXTRAPOLATION CASES 
C        
      DO 30 I=1,N  
      IF(Y(I).GT.X(1)) B(I)=A(1)+((A(1)-A(2))/(X(1)-X(2)))*(Y(I)-X(1))
      IF(Y(I).LT.X(M)) B(I)=A(M)       
 30   CONTINUE     
C        
C        INTERPOLATION CASES 
C        
      NM=M-1       
      DO 10 I=1,N  
      DO 20 J=1,NM 
      IF(Y(I).LE.X(J).AND.Y(I).GE.X(J+1))        
     +  B(I)=A(J) -(A(J)-A(J+1))*(X(J)-Y(I))/(X(J)-X(J+1)) 
 20   CONTINUE     
 10   CONTINUE     
C        
      RETURN       
      END