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C $Header: /u/gcmpack/MITgcm/pkg/zonal_filt/zonal_filter.F,v 1.5 2001/12/11 14:50:14 jmc Exp $ |
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C $Name: $ |
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|
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#include "ZONAL_FILT_OPTIONS.h" |
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|
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SUBROUTINE ZONAL_FILTER( |
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U field, fieldMask, |
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I jMin, jMax, kMin, kMax, bi, bj, gridLoc, myThid ) |
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C /==========================================================\ |
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C | S/R ZONAL_FILTER | |
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C | o Apply FFT filter to a latitude circle. | |
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C \==========================================================/ |
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IMPLICIT NONE |
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|
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C == Global data == |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "GRID.h" |
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#include "ZONAL_FILT.h" |
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#include "FFTPACK.h" |
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|
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C == Routine arguments == |
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C jMin - Range of points to filter |
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C jMax |
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C kMin |
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C kMax |
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C bi |
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C bj |
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C myThid - Thread number of this instance of FILTER_LATCIRC_FFT_APPLY |
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C field - Field to filter |
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C gridLoc - Orientation (U or V) of field. |
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INTEGER myThid |
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INTEGER gridLoc |
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Real*8 field(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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Real*8 fieldMask(1-Olx:sNx+Olx,1-Oly:sNy+Oly,Nr,nSx,nSy) |
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INTEGER jMin, jMax, kMin, kMax, bi, bj |
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|
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#ifdef ALLOW_ZONAL_FILT |
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|
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C == Local data == |
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Real*8 phi(Nx) |
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Real*8 phiMask(Nx) |
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Real*8 avPhi |
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INTEGER I, J, K |
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|
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DO k=kMin, kMax |
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DO j=jMin, jMax |
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IF ( (gridLoc.EQ.1 .AND.ABS(yC(1,j,bi,bj)).GE.zonal_filt_lat) |
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& .OR.(gridLoc.EQ.2 .AND.ABS(yG(2,j,bi,bj)).GE.zonal_filt_lat) |
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& .OR. zonal_filt_mode2dx.EQ.2 ) THEN |
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|
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C o Copy zonal line of field into local workspace |
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DO i=1,sNx |
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phi(I) = field(i,j,k,bi,bj) |
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phiMask(I) = fieldMask(i,j,k,bi,bj) |
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ENDDO |
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|
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C Interpolate through land |
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CALL ZONAL_FILT_PRESMOOTH( phiMask,phi,avPhi,sNx,myThid ) |
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|
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C o Forward transform (using specific FFT package) |
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C CALL R8FFTF( Nx, phi, FFTPACKWS(1,bj) ) |
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CALL R8FFTF1( Nx, phi, |
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& FFTPACKWS1(1,bj), FFTPACKWS2(1,bj),FFTPACKWS3(1,bj) ) |
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|
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C o Apply amplitude filter and normalize |
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IF (gridLoc .EQ. 1) THEN |
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DO i=1, Nx |
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phi(i)=phi(i)*ampFactor(i,j,bi,bj)/float(Nx) |
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ENDDO |
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ELSEIF (gridLoc .EQ. 2) THEN |
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DO i=1, Nx |
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phi(i)=phi(i)*ampFactorV(i,j,bi,bj)/float(Nx) |
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ENDDO |
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ELSE |
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WRITE(*,*) 'Error: gridLoc = ',gridLoc |
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STOP 'Error: gridLoc has illegal value' |
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ENDIF |
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|
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C o Backward transform (using specific FFT package) |
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C CALL R8FFTB( Nx, phi, FFTPACKWS(1,bj) ) |
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CALL R8FFTB1( Nx, phi, |
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& FFTPACKWS1(1,bj), FFTPACKWS2(1,bj),FFTPACKWS3(1,bj) ) |
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|
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C De-interpolate through land |
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CALL ZONAL_FILT_POSTSMOOTH(phiMask,phi,avPhi,sNx,myThid) |
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|
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C o Do periodic wrap around by hand |
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DO i=1-OLx,0 |
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field(i,j,k,bi,bj) = phi(sNx+i) |
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ENDDO |
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DO i=1,sNx |
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field(i,j,k,bi,bj) = phi(I) |
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ENDDO |
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DO i=sNx+1,sNx+OLx |
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field(i,j,k,bi,bj) = phi(i-sNx) |
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ENDDO |
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|
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ENDIF |
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ENDDO |
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ENDDO |
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|
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#endif /* ALLOW_ZONAL_FILT */ |
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|
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RETURN |
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END |
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