The following Fortran 77 program opens a file and reads vorticity and divergence (vo/d) spectral fields in GRIB format; it then calls INTUVP2 to create spectral U/V fields. Because of the preliminary call to INTOUT, the U/V fields are subsequently interpolated to grid-point fields with resolution 3 by 3 degrees without the need for a separate call to INTF. The function INTIN is not used here because the input fields are in GRIB format and are self-defining.
Subroutines PBOPEN, PBCLOSE, PBGRIB and PBWRITE handle pure binary input and output files.
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C C Copyright 2015 ECMWF. C C This software is licensed under the terms of the Apache Licence C Version 2.0 which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. C C Unless required by applicable law or agreed to in writing, software C distributed under the License is distributed on an "AS IS" BASIS, C WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. C C In applying this licence, ECMWF does not waive the privileges and immunities C granted to it by virtue of its status as an intergovernmental organisation C nor does it submit to any jurisdiction. C PROGRAM EXAMPLE_INTUVP2 IMPLICIT NONE C Parameters INTEGER JPGRIB ! GRIB size (up to 1/16 deg) INTEGER JPBYTES ! bytes/integer PARAMETER (JPGRIB = 33190420) #ifdef INTEGER_8 PARAMETER (JPBYTES = 8) #else PARAMETER (JPBYTES = 4) #endif C Local variables INTEGER INTV(4) REAL REALV(4) CHARACTER*20 CHARV CHARACTER*128 INFILE, OUTFILE, ARG INTEGER INLEN, OUTLEN, U1, U2, IRET, N INTEGER IVOGRIB(JPGRIB), IDVGRIB(JPGRIB) INTEGER IUGRIB(JPGRIB), IVGRIB(JPGRIB) C Externals INTEGER INTOUT, INTUVP2, IARGC C ------------------------------------------------------------------ C Pick up file names from command line INFILE = ' ' OUTFILE = ' ' IF( IARGC().EQ.4 ) THEN DO N = 1, 4, 2 CALL GETARG(N,ARG) IF (ARG.EQ.'-i') THEN CALL GETARG(N+1,INFILE) ELSEIF (ARG.EQ.'-o') THEN CALL GETARG(N+1,OUTFILE) ENDIF ENDDO ENDIF CALL CHECK( _ INDEX(INFILE,' ').EQ.1 .OR. INDEX(OUTFILE,' ').EQ.1, _ 'Usage: example_intuvp2 -i infile -o outfile' ) INTV = 0 REALV = 0. CHARV = '' C Define the grid interval for the output REALV(1) = 3.0 REALV(2) = 3.0 IRET = INTOUT('grid', INTV, REALV, CHARV) CALL CHECK(IRET.NE.0, 'INTOUT (grid) failed') REALV = 0. C Open input and output files CALL PBOPEN(U1, INFILE, 'r', IRET) CALL CHECK(IRET.NE.0, 'PBOPEN failed (r)') CALL PBOPEN(U2, OUTFILE, 'w', IRET) CALL CHECK(IRET.NE.0, 'PBOPEN failed (w)') C Start of loop on input vo/d pairs PRINT *, 'Start interpolation...' N = 0 220 CONTINUE N = N + 1 C Read next vo/d pair CALL PBGRIB(U1, IVOGRIB, JPGRIB * JPBYTES, INLEN, IRET) IF (IRET.EQ.-1) THEN IRET = 0 GOTO 290 ENDIF CALL CHECK(IRET.NE.0, 'PBGRIB failed (vo)') CALL PBGRIB(U1, IDVGRIB, JPGRIB * JPBYTES, INLEN, IRET) IF (IRET.EQ.-1) THEN IRET = 0 GOTO 290 ENDIF CALL CHECK(IRET.NE.0, 'PBGRIB failed (d)') C Interpolate PRINT *, 'Interpolate vo/d pair #', N OUTLEN = JPGRIB IRET = INTUVP2(IVOGRIB, IDVGRIB, JPGRIB, IUGRIB, IVGRIB, OUTLEN) CALL CHECK(IRET.NE.0, 'INTUVP failed') C Write the new u/v to file IF (OUTLEN.GT.0) THEN CALL PBWRITE(U2, IUGRIB, OUTLEN, IRET) CALL CHECK(IRET.LT.OUTLEN,'PBWRITE failed (vo)') CALL PBWRITE(U2, IVGRIB, OUTLEN, IRET) CALL CHECK(IRET.LT.OUTLEN,'PBWRITE failed (d)') ENDIF C Loop back for next vo/d pair GOTO 220 C Close 290 CONTINUE CALL PBCLOSE(U1, IRET) CALL PBCLOSE(U2, IRET) PRINT *, 'Interpolated ', (N-1), ' vo/d pair(s).' END C ------------------------------------------------------------------ SUBROUTINE CHECK(OOPS,MSG) IMPLICIT NONE LOGICAL OOPS CHARACTER MSG*(*) IF (OOPS) THEN PRINT *, MSG CALL EXIT(3) ENDIF END |