C----------------------------------------------------------------------- SUBROUTINE POLATEG4(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI, & NO,RLAT,RLON,CROT,SROT,IBO,LO,XO,YO,IRET) C$$$ SUBPROGRAM DOCUMENTATION BLOCK C C SUBPROGRAM: POLATEG4 INTERPOLATE SCALAR FIELD GRADIENTS (SPECTRAL) C PRGMMR: IREDELL ORG: W/NMC23 DATE: 96-04-10 C C ABSTRACT: THIS SUBPROGRAM PERFORMS SPECTRAL INTERPOLATION C FROM ANY GRID TO ANY GRID FOR SCALAR FIELDS, C RETURNING THEIR VECTOR GRADIENTS. C IT REQUIRES THAT THE INPUT FIELDS BE UNIFORMLY GLOBAL. C OPTIONS ALLOW CHOICES BETWEEN TRIANGULAR SHAPE (IPOPT(1)=0) C AND RHOMBOIDAL SHAPE (IPOPT(1)=1) WHICH HAS NO DEFAULT; C A SECOND OPTION IS THE TRUNCATION (IPOPT(2)) WHICH DEFAULTS C TO A SENSIBLE TRUNCATION FOR THE INPUT GRID (IF OPT(2)=-1). C NOTE THAT IF THE OUTPUT GRID IS NOT FOUND IN A SPECIAL LIST, C THEN THE TRANSFORM BACK TO GRID IS NOT VERY FAST. C THIS SPECIAL LIST CONTAINS GLOBAL CYLINDRICAL GRIDS, C POLAR STEREOGRAPHIC GRIDS CENTERED AT THE POLE C AND MERCATOR GRIDS. C ONLY HORIZONTAL INTERPOLATION IS PERFORMED. C THE GRIDS ARE DEFINED BY THEIR GRID DESCRIPTION SECTIONS C (PASSED IN INTEGER FORM AS DECODED BY SUBPROGRAM W3FI63). C THE CURRENT CODE RECOGNIZES THE FOLLOWING PROJECTIONS: C (KGDS(1)=000) EQUIDISTANT CYLINDRICAL C (KGDS(1)=001) MERCATOR CYLINDRICAL C (KGDS(1)=003) LAMBERT CONFORMAL CONICAL C (KGDS(1)=004) GAUSSIAN CYLINDRICAL (SPECTRAL NATIVE) C (KGDS(1)=005) POLAR STEREOGRAPHIC AZIMUTHAL C (KGDS(1)=202) ROTATED EQUIDISTANT CYLINDRICAL (ETA NATIVE) C WHERE KGDS COULD BE EITHER INPUT KGDSI OR OUTPUT KGDSO. C AS AN ADDED BONUS THE NUMBER OF OUTPUT GRID POINTS C AND THEIR LATITUDES AND LONGITUDES ARE ALSO RETURNED. C ON THE OTHER HAND, THE OUTPUT CAN BE A SET OF STATION POINTS C IF KGDSO(1)<0, IN WHICH CASE THE NUMBER OF POINTS C AND THEIR LATITUDES AND LONGITUDES MUST BE INPUT. C OUTPUT BITMAPS WILL NOT BE CREATED. C C PROGRAM HISTORY LOG: C 96-04-10 IREDELL C 2001-06-18 IREDELL IMPROVE DETECTION OF SPECIAL FAST TRANSFORM C C USAGE: CALL POLATEG4(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI, C & NO,RLAT,RLON,CROT,SROT,IBO,LO,GO,IRET) C C INPUT ARGUMENT LIST: C IPOPT - INTEGER (20) INTERPOLATION OPTIONS C IPOPT(1)=0 FOR TRIANGULAR, IPOPT(1)=1 FOR RHOMBOIDAL; C IPOPT(2) IS TRUNCATION NUMBER C (DEFAULTS TO SENSIBLE IF IPOPT(2)=-1). C KGDSI - INTEGER (200) INPUT GDS PARAMETERS AS DECODED BY W3FI63 C KGDSO - INTEGER (200) OUTPUT GDS PARAMETERS C (KGDSO(1)<0 IMPLIES RANDOM STATION POINTS) C MI - INTEGER SKIP NUMBER BETWEEN INPUT GRID FIELDS IF KM>1 C OR DIMENSION OF INPUT GRID FIELDS IF KM=1 C MO - INTEGER SKIP NUMBER BETWEEN OUTPUT GRID FIELDS IF KM>1 C OR DIMENSION OF OUTPUT GRID FIELDS IF KM=1 C KM - INTEGER NUMBER OF FIELDS TO INTERPOLATE C IBI - INTEGER (KM) INPUT BITMAP FLAGS (MUST BE ALL 0) C LI - LOGICAL*1 (MI,KM) INPUT BITMAPS (IF SOME IBI(K)=1) C GI - REAL (MI,KM) INPUT FIELDS TO INTERPOLATE C NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)<0) C RLAT - REAL (NO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)<0) C RLON - REAL (NO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)<0) C CROT - REAL (NO) VECTOR ROTATION COSINES (IF KGDSO(1)<0) C SROT - REAL (NO) VECTOR ROTATION SINES (IF KGDSO(1)<0) C (UGRID=CROT*UEARTH-SROT*VEARTH; C VGRID=SROT*UEARTH+CROT*VEARTH) C C OUTPUT ARGUMENT LIST: C NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)>=0) C RLAT - REAL (MO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)>=0) C RLON - REAL (MO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)>=0) C IBO - INTEGER (KM) OUTPUT BITMAP FLAGS C LO - LOGICAL*1 (MO,KM) OUTPUT BITMAPS (ALWAYS OUTPUT) C GO - REAL (MO,KM) OUTPUT FIELDS INTERPOLATED C IRET - INTEGER RETURN CODE C 0 SUCCESSFUL INTERPOLATION C 2 UNRECOGNIZED INPUT GRID OR NO GRID OVERLAP C 3 UNRECOGNIZED OUTPUT GRID C 41 INVALID NONGLOBAL INPUT GRID C 42 INVALID SPECTRAL METHOD PARAMETERS C 43 UNIMPLEMENTED OUTPUT GRID C C SUBPROGRAMS CALLED: C GDSWZD GRID DESCRIPTION SECTION WIZARD C SPTRUN SPECTRALLY TRUNCATE GRIDDED SCALAR FIELDS C SPTRUNS SPECTRALLY INTERPOLATE SCALARS TO POLAR STEREO. C SPTRUNM SPECTRALLY INTERPOLATE SCALARS TO MERCATOR C SPTRUNG SPECTRALLY INTERPOLATE SCALARS TO STATIONS C C ATTRIBUTES: C LANGUAGE: FORTRAN 77 C C$$$ INTEGER IPOPT(20) INTEGER KGDSI(200),KGDSO(200) INTEGER IBI(KM),IBO(KM) LOGICAL*1 LI(MI,KM),LO(MO,KM) REAL GI(MI,KM),XO(MO,KM),YO(MO,KM) REAL RLAT(MO),RLON(MO) REAL CROT(MO),SROT(MO) REAL XPTS(MO),YPTS(MO) REAL GO2(MO,KM) PARAMETER(FILL=-9999.) PARAMETER(RERTH=6.3712E6) PARAMETER(PI=3.14159265358979,DPR=180./PI) C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C COMPUTE NUMBER OF OUTPUT POINTS AND THEIR LATITUDES AND LONGITUDES. IRET=0 IF(KGDSO(1).GE.0) THEN CALL GDSWZD(KGDSO, 0,MO,FILL,XPTS,YPTS,RLON,RLAT,NO,1,CROT,SROT, & 0,DUM,DUM,DUM,DUM) IF(NO.EQ.0) IRET=3 ENDIF C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C AFFIRM APPROPRIATE INPUT GRID C LAT/LON OR GAUSSIAN C NO BITMAPS C FULL ZONAL COVERAGE C FULL MERIDIONAL COVERAGE IDRTI=KGDSI(1) IM=KGDSI(2) JM=KGDSI(3) RLON1=KGDSI(5)*1.E-3 RLON2=KGDSI(8)*1.E-3 ISCAN=MOD(KGDSI(11)/128,2) JSCAN=MOD(KGDSI(11)/64,2) NSCAN=MOD(KGDSI(11)/32,2) IF(IDRTI.NE.0.AND.IDRTI.NE.4) IRET=41 DO K=1,KM IF(IBI(K).NE.0) IRET=41 ENDDO IF(IRET.EQ.0) THEN IF(ISCAN.EQ.0) THEN DLON=(MOD(RLON2-RLON1-1+3600,360.)+1)/(IM-1) ELSE DLON=-(MOD(RLON1-RLON2-1+3600,360.)+1)/(IM-1) ENDIF IG=NINT(360/ABS(DLON)) IPRIME=1+MOD(-NINT(RLON1/DLON)+IG,IG) IMAXI=IG JMAXI=JM IF(MOD(IG,2).NE.0.OR.IM.LT.IG) IRET=41 ENDIF IF(IRET.EQ.0.AND.IDRTI.EQ.0) THEN RLAT1=KGDSI(4)*1.E-3 RLAT2=KGDSI(7)*1.E-3 DLAT=(RLAT2-RLAT1)/(JM-1) JG=NINT(180/ABS(DLAT)) IF(JM.EQ.JG) IDRTI=256 IF(JM.NE.JG.AND.JM.NE.JG+1) IRET=41 ELSEIF(IRET.EQ.0.AND.IDRTI.EQ.4) THEN JG=KGDSI(10)*2 IF(JM.NE.JG) IRET=41 ENDIF C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C SET PARAMETERS IF(IRET.EQ.0) THEN IROMB=IPOPT(1) MAXWV=IPOPT(2) IF(MAXWV.EQ.-1) THEN IF(IROMB.EQ.0.AND.IDRTI.EQ.4) MAXWV=(JMAXI-1) IF(IROMB.EQ.1.AND.IDRTI.EQ.4) MAXWV=(JMAXI-1)/2 IF(IROMB.EQ.0.AND.IDRTI.EQ.0) MAXWV=(JMAXI-3)/2 IF(IROMB.EQ.1.AND.IDRTI.EQ.0) MAXWV=(JMAXI-3)/4 IF(IROMB.EQ.0.AND.IDRTI.EQ.256) MAXWV=(JMAXI-1)/2 IF(IROMB.EQ.1.AND.IDRTI.EQ.256) MAXWV=(JMAXI-1)/4 ENDIF IF((IROMB.NE.0.AND.IROMB.NE.1).OR.MAXWV.LT.0) IRET=42 ENDIF C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C INTERPOLATE IF(IRET.EQ.0) THEN IF(NSCAN.EQ.0) THEN ISKIPI=1 JSKIPI=IM ELSE ISKIPI=JM JSKIPI=1 ENDIF IF(ISCAN.EQ.1) ISKIPI=-ISKIPI IF(JSCAN.EQ.0) JSKIPI=-JSKIPI ISPEC=0 C SPECIAL CASE OF GLOBAL CYLINDRICAL GRID IF((KGDSO(1).EQ.0.OR.KGDSO(1).EQ.4).AND. & MOD(KGDSO(2),2).EQ.0.AND.KGDSO(5).EQ.0.AND. & KGDSO(11).EQ.0) THEN IDRTO=KGDSO(1) IMO=KGDSO(2) JMO=KGDSO(3) RLON2=KGDSO(8)*1.E-3 DLONO=(MOD(RLON2-1+3600,360.)+1)/(IMO-1) IGO=NINT(360/ABS(DLONO)) IF(IMO.EQ.IGO.AND.IDRTO.EQ.0) THEN RLAT1=KGDSO(4)*1.E-3 RLAT2=KGDSO(7)*1.E-3 DLAT=(RLAT2-RLAT1)/(JMO-1) JGO=NINT(180/ABS(DLAT)) IF(JMO.EQ.JGO) IDRTO=256 IF(JMO.EQ.JGO.OR.JMO.EQ.JGO+1) ISPEC=1 ELSEIF(IMO.EQ.IGO.AND.IDRTO.EQ.4) THEN JGO=KGDSO(10)*2 IF(JMO.EQ.JGO) ISPEC=1 ENDIF IF(ISPEC.EQ.1) THEN CALL SPTRUND(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,IDRTO,IMO,JMO, & KM,IPRIME,ISKIPI,JSKIPI,MI,0,0,MO,0,GI,GM, & XO,YO) ELSE IRET=43 ENDIF ELSE IRET=43 ENDIF ENDIF IF(IRET.EQ.0) THEN DO K=1,KM IBO(K)=0 DO N=1,NO LO(N,K)=.TRUE. ENDDO ENDDO ELSE CMIC$ DO ALL AUTOSCOPE DO K=1,KM IBO(K)=1 DO N=1,NO LO(N,K)=.FALSE. XO(N,K)=0. YO(N,K)=0. ENDDO ENDDO ENDIF C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - END