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|
C Copyright 1981-2007 ECMWF
C
C Licensed under the GNU Lesser General Public License which
C incorporates the terms and conditions of version 3 of the GNU
C General Public License.
C See LICENSE and gpl-3.0.txt for details.
C
INTEGER FUNCTION INTFAP(INGRIB,INLEN)
C
C---->
C**** INTFAP
C
C Purpose
C -------
C
C Prepare to interpolate input field...
C
C
C Interface
C ---------
C
C IRET = INTFAP(INGRIB,INLEN)
C
C Input
C -----
C
C INGRIB - Input field (packed).
C INLEN - Input field length (words).
C
C
C Output
C ------
C
C Field unpacked values are in ZNFELDI, rotated if necessary.
C
C Returns: 0, if OK. Otherwise, an error occured in interpolation.
C
C
C Method
C ------
C
C Unpack field.
C
C Rotate the field values if necessary.
C
C Some rotation coefficients cannot be created because the
C algorithm does not converge for rotations which are smaller
C than a limit which depends on the spectral truncation.
C
C If the rotation is too small, it has to be split into three
C steps (two forward and one backward).
C
C Current know limits are:
C
C Truncation Max South pole lat Minimum rotation
C ---------- ------------------ ----------------
C 63 -89.5 0.5
C 106 -85 5.0
C 159 -77 13.0
C 213 -68 22.0
C 319 -51 39.0
C 511 -30.5 59.5
C
C
C Externals
C ---------
C
C GRIBEX - Decode/encode GRIB product.
C GRSVCK - Turn off GRIB checking
C INTLOG - Log error message.
C INTLOGR - Log error message.
C RPHI - Rotate a spectral field by longitude.
#ifdef __uxp__
C JACOBIF - Rotates spectral coefficients by latitude.
#else
C JACOBI - Rotates spectral coefficients by latitude.
#endif
C
C
C Author
C ------
C
C J.D.Chambers ECMWF Jan 1995
C
C J.D.Chambers ECMWF Feb 1997
C Allow for 64-bit pointers
C
C J.D.Chambers ECMWF Oct 2000
C Split rotations if less than minimum for the truncation
C
C----<
C
C -----------------------------------------------------------------|
C* Section 0. Variables
C
C
IMPLICIT NONE
C
C Function arguments
INTEGER INGRIB(*),INLEN
C
#include "parim.h"
#include "nifld.common"
#include "nofld.common"
#include "grfixed.h"
#include "intf.h"
C
C Parameters
INTEGER JPROUTINE
PARAMETER (JPROUTINE = 26200 )
INTEGER JPLEN, JPNM
PARAMETER ( JPNM = JPSTRUNC )
PARAMETER ( JPLEN = (JPNM+1)*(JPNM+6) )
C
C Local variables
C
REAL POLELAT, POLELON
CHARACTER*1 TYPE
INTEGER NUMPTS, NGAUSS
INTEGER IWORD, IERR, KPR, NBYTES, ITRUNC, LOOP, IRET
INTEGER ISIZE
DATA ISIZE/0/
C
REAL SWORK
DIMENSION SWORK(1)
#ifdef POINTER_64
INTEGER*8 ISWORK
#endif
POINTER ( ISWORK, SWORK)
C
REAL*8 DWORK
DIMENSION DWORK(1)
#ifdef POINTER_64
INTEGER*8 IDWORK
#endif
POINTER ( IDWORK, DWORK)
C
REAL*8 DATA
DIMENSION DATA(1)
#ifdef POINTER_64
INTEGER*8 IDATA
#endif
POINTER ( IDATA, DATA)
C
SAVE ISIZE, ISWORK, IDWORK, IDATA
C
REAL*8 DLON, DLAT, LATLIM
LOGICAL LOK, LSPLIT
#ifdef CRAY
DATA NBYTES/8/
#else
DATA NBYTES/4/
#endif
C
C Externals
INTEGER NGROTAT
#ifdef __uxp__
LOGICAL JACOBIF
EXTERNAL JACOBIF
#else
LOGICAL JACOBI
EXTERNAL JACOBI
#endif
C
C -----------------------------------------------------------------|
C* Section 1. Initialise
C -----------------------------------------------------------------|
C
100 CONTINUE
INTFAP = 0
IERR = 0
KPR = 0
C
C -----------------------------------------------------------------|
C* Section 2. Decode data from the GRIB code
C -----------------------------------------------------------------|
C
200 CONTINUE
C
C Decode data from GRIB code (no checking)
C
IWORD = INLEN
IERR = 0
CALL GRSVCK(0)
IERR = 1
ISEC3(2) = NINT(RMISSGV)
ZSEC3(2) = RMISSGV
CALL GRIBEX(ISEC0, ISEC1, ISEC2, ZSEC2, ISEC3, ZSEC3, ISEC4,
X ZNFELDI, JPEXPAND, INGRIB, INLEN, IWORD, 'D',IERR)
C
IF( IERR.LT.0) THEN
IF( (IERR.EQ.-2).OR.(IERR.EQ.-4) ) THEN
CALL INTLOG(JP_DEBUG,'INTFAP: Use missing value',JPQUIET)
LIMISSV = .TRUE.
ELSE
CALL INTLOG(JP_ERROR,'INTFAP: GRIBEX decoding fail.',IERR)
INTFAP = IERR
GOTO 900
ENDIF
ELSE IF( IERR.GT.0 ) THEN
CALL INTLOG(JP_ERROR,'INTFAP: GRIBEX decoding failed.',IERR)
INTFAP = IERR
GOTO 900
ENDIF
C
C -----------------------------------------------------------------|
C* Section 3. Handle spectral rotation, if necessary.
C -----------------------------------------------------------------|
C
300 CONTINUE
C
C Is the interpolation from SH with a rotation of the SH first?
C
IF( ((NIREPR.EQ.JPSPHERE).OR.(NIREPR.EQ.JPSPHROT)) .AND.
X LNOROTA ) THEN
C
C Avoid rotating U or V spectral coefficients
C
IF( (NIPARAM.EQ.131).OR.(NIPARAM.EQ.132) ) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Unable to rotate spectral U or V:',NIPARAM)
INTFAP = JPROUTINE + 6
GOTO 900
ENDIF
C
C Dynamically allocate memory for workspace.
C
C (Note the multiplication by 2 for REAL*8).
C
ISIZE = (2*(JPNM+1)*(JPNM+6))*2
CALL JMEMHAN( 11, IDWORK, ISIZE, 1, IRET)
IF( IRET.NE.0 ) THEN
CALL INTLOG(JP_ERROR,'INTFAP: memory allocation fail',IDWORK)
INTFAP = JPROUTINE + 1
GOTO 900
ENDIF
C
C (Note the multiplication by 2 for REAL*8).
C
ISIZE = JPLEN*2
CALL JMEMHAN( 15, IDATA, ISIZE, 1, IRET)
IF( IRET.NE.0 ) THEN
CALL INTLOG(JP_ERROR,'INTFAP: memory allocation fail',IDATA)
INTFAP = JPROUTINE + 2
GOTO 900
ENDIF
C
CALL INTLOG(JP_DEBUG,'INTFAP: Rotate SH field.',JPQUIET)
CALL INTLOG(JP_DEBUG,'INTFAP: South pole latitude ',NOROTA(1))
CALL INTLOG(JP_DEBUG,'INTFAP: South pole longitude ',NOROTA(2))
IF ( NOREPR.EQ.JPSPHERE ) NOREPR = JPSPHROT
IF ( NOREPR.EQ.JPREGULAR ) NOREPR = JPREGROT
ITRUNC = ISEC2(2)
C
C Some rotation coefficients cannot be created because the
C algorithm does not converge for rotations which are smaller
C than a limit which depends on the spectral truncation.
C
IF( ITRUNC.LE.63 ) THEN
LATLIM = -89.5
ELSE IF( ITRUNC.LE.106 ) THEN
LATLIM = -85.0
ELSE IF( ITRUNC.LE.159 ) THEN
LATLIM = -77.0
ELSE IF( ITRUNC.LE.213 ) THEN
LATLIM = -68.0
ELSE IF( ITRUNC.LE.319 ) THEN
LATLIM = -51.0
ELSE IF( ITRUNC.LE.511 ) THEN
#ifdef __uxp__
LATLIM = -30.5
#else
LATLIM = -29.5
#endif
ELSE
INTFAP = JPROUTINE + 7
GOTO 900
ENDIF
CALL INTLOGR(JP_DEBUG,
X 'INTFAP: South pole latitude limit = ',LATLIM)
C
POLELAT = (REAL(NOROTA(1))/JPMULT)
C
C If the rotation is too small, it has to be split into three
C steps (two forward and one backward).
C
LSPLIT = POLELAT.LT.LATLIM
IF( LSPLIT ) THEN
DLAT = -90.0 - LATLIM
CALL INTLOG(JP_DEBUG,
X 'INTFAP: Rotation has been split into three steps',JPQUIET)
ELSE
DLAT = -90.0 - POLELAT
ENDIF
#if (defined CRAY) || (defined REAL_8)
C
C Double precision REALs
C
DLON = - REAL(NOROTA(2))/JPMULT
C
C Rotate the spectral field by longitude.
CALL RPHI( ZNFELDI, ITRUNC, DWORK, DLON)
C
C Rotate the spectral field by latitude.
C
IF( LSPLIT ) THEN
C
C Two rotations forward ..
C
CALL INTLOGR(JP_DEBUG,
X 'INTFAP: Twice forward through angle ', DLAT)
#if (!defined __uxp__)
LOK = JACOBI(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
LOK = JACOBI(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#else
LOK = JACOBIF(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
LOK = JACOBIF(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#endif
C
C .. and one backward
C
DLAT = -90.0 - ( (LATLIM*2.0) - POLELAT)
DLAT= -DLAT
CALL INTLOGR(JP_DEBUG,
X 'INTFAP: Once backward through angle ', DLAT)
ENDIF
C
#if (!defined __uxp__)
LOK = JACOBI( ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#else
LOK = JACOBIF(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#endif
#else
C
C Single precision REALs; so convert to double precision.
C
DLAT = -90.0 - DBLE(NOROTA(1))/JPMULT
DLON = - DBLE(NOROTA(2))/JPMULT
C
C Expand spectral coefficients to REAL*8
C
DO LOOP = 1, ISEC4(1)
DATA(LOOP) = DBLE(ZNFELDI(LOOP))
ENDDO
C
C Rotate the spectral field by longitude.
CALL RPHI( DATA, ITRUNC, DWORK, DLON)
C
C Rotate the spectral field by latitude.
C
IF( LSPLIT ) THEN
C
C Two rotations forward ..
C
CALL INTLOGR(JP_DEBUG,
X 'INTFAP: Twice forward through angle ', DLAT)
#if (!defined __uxp__)
LOK = JACOBI(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
LOK = JACOBI(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#else
LOK = JACOBIF(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
LOK = JACOBIF(ZNFELDI, ITRUNC, DWORK, DLAT)
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,
X 'INTFAP: Spectral rotation failed',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#endif
C
C .. and one backward
C
DLAT = -90.0 - ( (LATLIM*2.0) - POLELAT)
DLAT= -DLAT
CALL INTLOGR(JP_DEBUG,
X 'INTFAP: Once backward through angle ', DLAT)
ENDIF
C
#if (!defined __uxp__)
LOK = JACOBI( DATA, ITRUNC, DWORK, DLAT)
#else
LOK = JACOBIF(DATA, ITRUNC, DWORK, DLAT)
#endif
#endif
C
IF(.NOT.LOK) THEN
CALL INTLOG(JP_ERROR,'INTFAP: Spectral rotation fail',JPQUIET)
INTFAP = JPROUTINE + 3
GOTO 900
ENDIF
#if (!defined CRAY) && (!defined REAL_8)
C
C Single precision REALs; repack spectral coefficients to REAL*4.
C
DO LOOP = 1, ISEC4(1)
ZNFELDI(LOOP) = SNGL(DATA(LOOP))
ENDDO
#endif
C
ENDIF
C
C -----------------------------------------------------------------|
C* Section 4. Handle gaussian rotation, if necessary.
C -----------------------------------------------------------------|
C
400 CONTINUE
C
C Is the interpolation from gaussian with a rotation of the
C gaussian first?
C
IF( ((NIREPR.EQ.JPGAUSSIAN).OR.(NIREPR.EQ.JPQUASI)) .AND.
X LNOROTA ) THEN
C
CALL INTLOG(JP_DEBUG,'INTFAP: Rotate gaussian field.',JPQUIET)
CALL INTLOG(JP_DEBUG,'INTFAP: South pole latitude ',NOROTA(1))
CALL INTLOG(JP_DEBUG,'INTFAP: South pole longitude ',NOROTA(2))
C
C Dynamically allocate memory for workspace.
C
NUMPTS = ISEC4(1)
ISIZE = NUMPTS
CALL JMEMHAN( 11, ISWORK, ISIZE, 1, IRET)
IF( IRET.NE.0 ) THEN
CALL INTLOG(JP_ERROR,'INTFAP: memory allocation fail',ISWORK)
INTFAP = JPROUTINE + 4
GOTO 900
ENDIF
C
C Rotate the gaussian field.
C
POLELAT = REAL(NOROTA(1))/JPMULT
POLELON = REAL(NOROTA(2))/JPMULT
NGAUSS = ISEC2(3)/2
IF( NIREPR.EQ.JPGAUSSIAN ) THEN
TYPE = 'F'
ELSE
TYPE = 'R'
ENDIF
IRET = NGROTAT(ZNFELDI,SWORK,NUMPTS,POLELAT,POLELON,TYPE,NGAUSS)
IF( IRET.NE.0 ) THEN
CALL INTLOG(JP_ERROR,'INTFAP: Gaussian rotation fail',JPQUIET)
INTFAP = JPROUTINE + 5
GOTO 900
ENDIF
C
C Move rotated field back into field original array.
C
DO LOOP = 1, NUMPTS
ZNFELDI(LOOP) = SWORK(LOOP)
ENDDO
C
ENDIF
C
C
C -----------------------------------------------------------------|
C* Section 9. Closedown.
C -----------------------------------------------------------------|
C
900 CONTINUE
C
RETURN
END
|
