MODULE GDSWZD_EQUID_CYLIND_MOD !$$$ MODULE DOCUMENTATION BLOCK ! ! $Revision: 74917 $ ! ! MODULE: GDSWZD_EQUID_CYLIND_MOD GDS WIZARD MODULE FOR EQUIDISTANT ! CYLINDRICAL GRIDS ! PRGMMR: GAYNO ORG: W/NMC23 DATE: 2015-01-21 ! ! ABSTRACT: - CONVERT FROM EARTH TO GRID COORDINATES OR VICE VERSA. ! - COMPUTE VECTOR ROTATION SINES AND COSINES. ! - COMPUTE MAP JACOBIANS. ! - COMPUTE GRID BOX AREA. ! ! PROGRAM HISTORY LOG: ! 2015-01-21 GAYNO INITIAL VERSION FROM A MERGER OF ! ROUTINES GDSWIZ00 AND GDSWZD00. ! 2015-09-17 GAYNO RENAME MODULE TO "GDSWZD_EQUID_CYLIND_MOD" ! ! USAGE: "USE GDSWZD_EQUID_CYLIND_MOD" THEN CALL THE PUBLIC DRIVER ! ROUTINE "GDSWZD_EQUID_CYLIND" ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ ! IMPLICIT NONE PRIVATE PUBLIC :: GDSWZD_EQUID_CYLIND REAL :: DLAT ! GRID RESOLUTION IN DEGREES N/S DIRECTION REAL :: DLON ! GRID RESOLUTION IN DEGREES E/W DIRECTION REAL :: RERTH CONTAINS SUBROUTINE GDSWZD_EQUID_CYLIND(IGDTNUM,IGDTMPL,IGDTLEN,IOPT,NPTS,FILL, & XPTS,YPTS,RLON,RLAT,NRET, & CROT,SROT,XLON,XLAT,YLON,YLAT,AREA) !$$$ SUBPROGRAM DOCUMENTATION BLOCK ! ! SUBPROGRAM: GDSWZD_EQUID_CYLIND GDS WIZARD FOR EQUIDISTANT CYLINDRICAL ! PRGMMR: IREDELL ORG: W/NMC23 DATE: 96-04-10 ! ! ABSTRACT: THIS SUBPROGRAM DECODES THE GRIB 2 GRID DEFINITION ! TEMPLATE (PASSED IN INTEGER FORM AS DECODED BY THE ! NCEP G2 LIBRARY) AND RETURNS ONE OF THE FOLLOWING: ! (IOPT=+1) EARTH COORDINATES OF SELECTED GRID COORDINATES ! (IOPT=-1) GRID COORDINATES OF SELECTED EARTH COORDINATES ! WORKS FOR EQUIDISTANT CYLINDRICAL PROJECTIONS. ! IF THE SELECTED COORDINATES ARE MORE THAN ONE GRIDPOINT ! BEYOND THE THE EDGES OF THE GRID DOMAIN, THEN THE RELEVANT ! OUTPUT ELEMENTS ARE SET TO FILL VALUES. THE ACTUAL ! NUMBER OF VALID POINTS COMPUTED IS RETURNED TOO. ! OPTIONALLY, THE VECTOR ROTATIONS, MAP JACOBIANS AND ! GRID BOX AREAS MAY BE RETURNED. TO COMPUTE THE VECTOR ! ROTATIONS, THE OPTIONAL ARGUMENTS 'SROT' AND 'CROT' ! MUST BE PRESENT. TO COMPUTE THE MAP JACOBIANS, THE ! OPTIONAL ARGUMENTS 'XLON', 'XLAT', 'YLON', 'YLAT' MUST ! BE PRESENT. TO COMPUTE THE GRID BOX AREAS, THE OPTIONAL ! ARGUMENT 'AREA' MUST BE PRESENT. ! ! PROGRAM HISTORY LOG: ! 96-04-10 IREDELL ! 97-10-20 IREDELL INCLUDE MAP OPTIONS ! 2015-01-21 GAYNO MERGER OF GDSWIZ00 AND GDSWZD00. MAKE ! CROT,SORT,XLON,XLAT,YLON,YLAT AND AREA ! OPTIONAL ARGUMENTS. MAKE PART OF A MODULE. ! MOVE VECTOR ROTATION, MAP JACOBIAN AND GRID ! BOX AREA COMPUTATIONS TO SEPARATE SUBROUTINES. ! 2015-07-13 GAYNO CONVERT TO GRIB 2. REPLACE GRIB 1 KGDS ARRAY ! WITH GRIB 2 GRID DEFINITION TEMPLATE ARRAY. ! RENAME ROUTINE AS "GDSWZD_EQUID_CYLIND". ! ! USAGE: CALL GDSWZD_EQUID_CYLIND(IGDTNUM,IGDTMPL,IGDTLEN,IOPT,NPTS, ! & FILL,XPTS,YPTS,RLON,RLAT,NRET, ! & CROT,SROT,XLON,XLAT,YLON,YLAT,AREA) ! ! INPUT ARGUMENT LIST: ! IGDTNUM - INTEGER GRID DEFINITION TEMPLATE NUMBER. ! CORRESPONDS TO THE GFLD%IGDTNUM COMPONENT OF THE ! NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE. ! MUST BE "0" FOR EQUIDISTANT CYLINDRICAL ! PROJECTIONS. ! IGDTMPL - INTEGER (IGDTLEN) GRID DEFINITION TEMPLATE ARRAY. ! CORRESPONDS TO THE GFLD%IGDTMPL COMPONENT OF THE ! NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE FOR SECTION ! THREE: ! (1): SHAPE OF EARTH, OCTET 15 ! (2): SCALE FACTOR OF SPHERICAL EARTH RADIUS, ! OCTET 16 ! (3): SCALED VALUE OF RADIUS OF SPHERICAL EARTH, ! OCTETS 17-20 ! (4): SCALE FACTOR OF MAJOR AXIS OF ELLIPTICAL EARTH, ! OCTET 21 ! (5): SCALED VALUE OF MAJOR AXIS OF ELLIPTICAL EARTH, ! OCTETS 22-25 ! (6): SCALE FACTOR OF MINOR AXIS OF ELLIPTICAL EARTH, ! OCTET 26 ! (7): SCALED VALUE OF MINOR AXIS OF ELLIPTICAL EARTH, ! OCTETS 27-30 ! (8): NUMBER OF POINTS ALONG A PARALLEL, OCTS 31-34 ! (9): NUMBER OF POINTS ALONG A MERIDIAN, OCTS 35-38 ! (10): BASIC ANGLE OF INITIAL PRODUCTION DOMAIN, ! OCTETS 39-42. ! (11): SUBDIVISIONS OF BASIC ANGLE, OCTETS 43-46 ! (12): LATITUDE OF FIRST GRID POINT, OCTETS 47-50 ! (13): LONGITUDE OF FIRST GRID POINT, OCTETS 51-54 ! (14): RESOLUTION AND COMPONENT FLAGS, OCTET 55 ! (15): LATITUDE OF LAST GRID POINT, OCTETS 56-59 ! (16): LONGITUDE OF LAST GRID POINT, OCTETS 60-63 ! (17): I-DIRECTION INCREMENT, OCTETS 64-67 ! (18): J-DIRECTION INCREMENT, OCTETS 68-71 ! (19): SCANNING MODE, OCTET 72 ! IGDTLEN - INTEGER NUMBER OF ELEMENTS (19) OF THE GRID DEFINITION ! TEMPLATE ARRAY. CORRESPONDS TO THE GFLD%IGDTLEN ! COMPONENT OF THE NCEP G2 LIBRARY GRIDMOD DATA STRUCTURE. ! IOPT - INTEGER OPTION FLAG ! (+1 TO COMPUTE EARTH COORDS OF SELECTED GRID COORDS) ! (-1 TO COMPUTE GRID COORDS OF SELECTED EARTH COORDS) ! NPTS - INTEGER MAXIMUM NUMBER OF COORDINATES ! FILL - REAL FILL VALUE TO SET INVALID OUTPUT DATA ! (MUST BE IMPOSSIBLE VALUE; SUGGESTED VALUE: -9999.) ! XPTS - REAL (NPTS) GRID X POINT COORDINATES IF IOPT>0 ! YPTS - REAL (NPTS) GRID Y POINT COORDINATES IF IOPT>0 ! RLON - REAL (NPTS) EARTH LONGITUDES IN DEGREES E IF IOPT<0 ! (ACCEPTABLE RANGE: -360. TO 360.) ! RLAT - REAL (NPTS) EARTH LATITUDES IN DEGREES N IF IOPT<0 ! (ACCEPTABLE RANGE: -90. TO 90.) ! ! OUTPUT ARGUMENT LIST: ! XPTS - REAL (NPTS) GRID X POINT COORDINATES IF IOPT<0 ! YPTS - REAL (NPTS) GRID Y POINT COORDINATES IF IOPT<0 ! RLON - REAL (NPTS) EARTH LONGITUDES IN DEGREES E IF IOPT>0 ! RLAT - REAL (NPTS) EARTH LATITUDES IN DEGREES N IF IOPT>0 ! NRET - INTEGER NUMBER OF VALID POINTS COMPUTED ! CROT - REAL, OPTIONAL (NPTS) CLOCKWISE VECTOR ROTATION COSINES ! SROT - REAL, OPTIONAL (NPTS) CLOCKWISE VECTOR ROTATION SINES ! (UGRID=CROT*UEARTH-SROT*VEARTH; ! VGRID=SROT*UEARTH+CROT*VEARTH) ! XLON - REAL, OPTIONAL (NPTS) DX/DLON IN 1/DEGREES ! XLAT - REAL, OPTIONAL (NPTS) DX/DLAT IN 1/DEGREES ! YLON - REAL, OPTIONAL (NPTS) DY/DLON IN 1/DEGREES ! YLAT - REAL, OPTIONAL (NPTS) DY/DLAT IN 1/DEGREES ! AREA - REAL, OPTIONAL (NPTS) AREA WEIGHTS IN M**2 ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ IMPLICIT NONE ! INTEGER, INTENT(IN ) :: IGDTNUM, IGDTLEN INTEGER, INTENT(IN ) :: IGDTMPL(IGDTLEN) INTEGER, INTENT(IN ) :: IOPT, NPTS INTEGER, INTENT( OUT) :: NRET ! REAL, INTENT(IN ) :: FILL REAL, INTENT(INOUT) :: RLON(NPTS),RLAT(NPTS) REAL, INTENT(INOUT) :: XPTS(NPTS),YPTS(NPTS) REAL, OPTIONAL, INTENT( OUT) :: CROT(NPTS),SROT(NPTS) REAL, OPTIONAL, INTENT( OUT) :: XLON(NPTS),XLAT(NPTS) REAL, OPTIONAL, INTENT( OUT) :: YLON(NPTS),YLAT(NPTS),AREA(NPTS) ! INTEGER :: IM, JM, ISCAN, N, ISCALE ! LOGICAL :: LROT, LMAP, LAREA ! REAL :: ECCEN_SQUARED REAL :: HI, RLAT1, RLON1, RLAT2, RLON2 REAL :: XMAX, XMIN, YMAX, YMIN ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - IF(PRESENT(CROT)) CROT=FILL IF(PRESENT(SROT)) SROT=FILL IF(PRESENT(XLON)) XLON=FILL IF(PRESENT(XLAT)) XLAT=FILL IF(PRESENT(YLON)) YLON=FILL IF(PRESENT(YLAT)) YLAT=FILL IF(PRESENT(AREA)) AREA=FILL ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! IS THIS AN EQUIDISTANT CYCLINDRICAL GRID? IF(IGDTNUM/=0)THEN CALL EQUID_CYLIND_ERROR(IOPT,FILL,RLAT,RLON,XPTS,YPTS,NPTS) RETURN ENDIF ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CALL EARTH_RADIUS(IGDTMPL,IGDTLEN,RERTH,ECCEN_SQUARED) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! ENSURE EARTH RADIUS IS DEFINED. IF(RERTH<0.) THEN CALL EQUID_CYLIND_ERROR(IOPT,FILL,RLAT,RLON,XPTS,YPTS,NPTS) RETURN ENDIF ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - IM=IGDTMPL(8) JM=IGDTMPL(9) ISCALE=IGDTMPL(10)*IGDTMPL(11) IF(ISCALE==0) ISCALE=10**6 RLAT1=FLOAT(IGDTMPL(12))/FLOAT(ISCALE) RLON1=FLOAT(IGDTMPL(13))/FLOAT(ISCALE) RLAT2=FLOAT(IGDTMPL(15))/FLOAT(ISCALE) RLON2=FLOAT(IGDTMPL(16))/FLOAT(ISCALE) ISCAN=MOD(IGDTMPL(19)/128,2) HI=(-1.)**ISCAN ! WNE DLON=HI*(MOD(HI*(RLON2-RLON1)-1+3600,360.)+1)/(IM-1) if (HI.eq.1) then if (RLON2 <= RLON1) RLON2 = RLON2 + 360.0 DLON = (RLON2-RLON1)/(IM-1) else if (RLON1 <= RLON2) RLON1 = RLON1 + 360.0 DLON = (RLON1-RLON2)/(IM-1) endif DLAT=(RLAT2-RLAT1)/(JM-1) XMIN=0 XMAX=IM+1 IF(IM.EQ.NINT(360/ABS(DLON))) XMAX=IM+2 YMIN=0 YMAX=JM+1 NRET=0 IF(PRESENT(CROT).AND.PRESENT(SROT))THEN LROT=.TRUE. ELSE LROT=.FALSE. ENDIF IF(PRESENT(XLON).AND.PRESENT(XLAT).AND.PRESENT(YLON).AND.PRESENT(YLAT))THEN LMAP=.TRUE. ELSE LMAP=.FALSE. ENDIF IF(PRESENT(AREA))THEN LAREA=.TRUE. ELSE LAREA=.FALSE. ENDIF ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! TRANSLATE GRID COORDINATES TO EARTH COORDINATES IF(IOPT.EQ.0.OR.IOPT.EQ.1) THEN !$OMP PARALLEL DO PRIVATE(N) REDUCTION(+:NRET) SCHEDULE(STATIC) DO N=1,NPTS IF(XPTS(N).GE.XMIN.AND.XPTS(N).LE.XMAX.AND. & YPTS(N).GE.YMIN.AND.YPTS(N).LE.YMAX) THEN RLON(N)=MOD(RLON1+DLON*(XPTS(N)-1)+3600,360.) RLAT(N)=MIN(MAX(RLAT1+DLAT*(YPTS(N)-1),-90.),90.) NRET=NRET+1 IF(LROT) CALL EQUID_CYLIND_VECT_ROT(CROT(N),SROT(N)) IF(LMAP) CALL EQUID_CYLIND_MAP_JACOB(XLON(N),XLAT(N),YLON(N),YLAT(N)) IF(LAREA) CALL EQUID_CYLIND_GRID_AREA(RLAT(N),AREA(N)) ELSE RLON(N)=FILL RLAT(N)=FILL ENDIF ENDDO !$OMP END PARALLEL DO ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ! TRANSLATE EARTH COORDINATES TO GRID COORDINATES ELSEIF(IOPT.EQ.-1) THEN !$OMP PARALLEL DO PRIVATE(N) REDUCTION(+:NRET) SCHEDULE(STATIC) DO N=1,NPTS IF(ABS(RLON(N)).LE.360.AND.ABS(RLAT(N)).LE.90) THEN XPTS(N)=1+HI*MOD(HI*(RLON(N)-RLON1)+3600,360.)/DLON YPTS(N)=1+(RLAT(N)-RLAT1)/DLAT IF(XPTS(N).GE.XMIN.AND.XPTS(N).LE.XMAX.AND. & YPTS(N).GE.YMIN.AND.YPTS(N).LE.YMAX) THEN NRET=NRET+1 IF(LROT) CALL EQUID_CYLIND_VECT_ROT(CROT(N),SROT(N)) IF(LMAP) CALL EQUID_CYLIND_MAP_JACOB(XLON(N),XLAT(N),YLON(N),YLAT(N)) IF(LAREA) CALL EQUID_CYLIND_GRID_AREA(RLAT(N),AREA(N)) ELSE XPTS(N)=FILL YPTS(N)=FILL ENDIF ELSE XPTS(N)=FILL YPTS(N)=FILL ENDIF ENDDO !$OMP END PARALLEL DO ENDIF ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - END SUBROUTINE GDSWZD_EQUID_CYLIND ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SUBROUTINE EQUID_CYLIND_ERROR(IOPT,FILL,RLAT,RLON,XPTS,YPTS,NPTS) !$$$ SUBPROGRAM DOCUMENTATION BLOCK ! ! SUBPROGRAM: EQUID_CYLIND_ERROR ERROR HANDLER ! PRGMMR: GAYNO ORG: W/NMC23 DATE: 2015-07-13 ! ! ABSTRACT: UPON AN ERROR, THIS SUBPROGRAM ASSIGNS ! A "FILL" VALUE TO THE OUTPUT FIELDS. ! ! PROGRAM HISTORY LOG: ! 2015-07-13 GAYNO INITIAL VERSION ! ! USAGE: CALL EQUID_CYLIND_ERROR(IOPT,FILL,RLAT,RLON,XPTS,YPTS,NPTS) ! ! INPUT ARGUMENT LIST: ! IOPT - INTEGER OPTION FLAG ! (+1 TO COMPUTE EARTH COORDS OF SELECTED GRID COORDS) ! (-1 TO COMPUTE GRID COORDS OF SELECTED EARTH COORDS) ! NPTS - INTEGER MAXIMUM NUMBER OF COORDINATES ! FILL - REAL FILL VALUE TO SET INVALID OUTPUT DATA ! (MUST BE IMPOSSIBLE VALUE; SUGGESTED VALUE: -9999.) ! OUTPUT ARGUMENT LIST: ! RLON - REAL (NPTS) EARTH LONGITUDES IN DEGREES E IF IOPT<0 ! RLAT - REAL (NPTS) EARTH LATITUDES IN DEGREES N IF IOPT<0 ! XPTS - REAL (NPTS) GRID X POINT COORDINATES IF IOPT>0 ! YPTS - REAL (NPTS) GRID Y POINT COORDINATES IF IOPT>0 ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ IMPLICIT NONE ! INTEGER, INTENT(IN ) :: IOPT, NPTS ! REAL, INTENT(IN ) :: FILL REAL, INTENT( OUT) :: RLAT(NPTS),RLON(NPTS) REAL, INTENT( OUT) :: XPTS(NPTS),YPTS(NPTS) ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - IF(IOPT>=0) THEN RLON=FILL RLAT=FILL ENDIF IF(IOPT<=0) THEN XPTS=FILL YPTS=FILL ENDIF ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - END SUBROUTINE EQUID_CYLIND_ERROR ! SUBROUTINE EQUID_CYLIND_VECT_ROT(CROT,SROT) !$$$ SUBPROGRAM DOCUMENTATION BLOCK ! ! SUBPROGRAM: EQUID_CYLIND_VECT_ROT VECTOR ROTATION FIELDS FOR ! EQUIDISTANT CYLINDRICAL GRIDS ! ! PRGMMR: GAYNO ORG: W/NMC23 DATE: 2015-01-21 ! ! ABSTRACT: THIS SUBPROGRAM COMPUTES THE VECTOR ROTATION SINES AND ! COSINES FOR AN EQUIDISTANT CYLINDRICAL GRID. ! ! PROGRAM HISTORY LOG: ! 2015-01-21 GAYNO INITIAL VERSION ! 2015-09-17 GAYNO RENAME AS "EQUID_CYLIND_VECT_ROT" ! ! USAGE: CALL EQUID_CYLIND_VECT_ROT(CROT,SROT) ! ! INPUT ARGUMENT LIST: ! NONE ! ! OUTPUT ARGUMENT LIST: ! CROT - CLOCKWISE VECTOR ROTATION COSINES (REAL) ! SROT - CLOCKWISE VECTOR ROTATION SINES (REAL) ! (UGRID=CROT*UEARTH-SROT*VEARTH; ! VGRID=SROT*UEARTH+CROT*VEARTH) ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ IMPLICIT NONE REAL, INTENT( OUT) :: CROT, SROT CROT=1.0 SROT=0.0 END SUBROUTINE EQUID_CYLIND_VECT_ROT ! SUBROUTINE EQUID_CYLIND_MAP_JACOB(XLON,XLAT,YLON,YLAT) !$$$ SUBPROGRAM DOCUMENTATION BLOCK ! ! SUBPROGRAM: EQUID_CYLIND_MAP_JACOB MAP JACOBIANS FOR ! EQUIDISTANT CYLINDRICAL GRIDS ! ! PRGMMR: GAYNO ORG: W/NMC23 DATE: 2015-01-21 ! ! ABSTRACT: THIS SUBPROGRAM COMPUTES THE MAP JACOBIANS FOR ! AN EQUIDISTANT CYLINDRICAL GRID. ! ! PROGRAM HISTORY LOG: ! 2015-01-21 GAYNO INITIAL VERSION ! 2015-09-17 GAYNO RENAME AS "EQUID_CYLIND_MAP_JACOB" ! ! USAGE: CALL EQUID_CYLIND_MAP_JACOB(XLON,XLAT,YLON,YLAT) ! ! INPUT ARGUMENT LIST: ! NONE ! ! OUTPUT ARGUMENT LIST: ! XLON - DX/DLON IN 1/DEGREES (REAL) ! XLAT - DX/DLAT IN 1/DEGREES (REAL) ! YLON - DY/DLON IN 1/DEGREES (REAL) ! YLAT - DY/DLAT IN 1/DEGREES (REAL) ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ REAL, INTENT( OUT) :: XLON,XLAT,YLON,YLAT XLON=1.0/DLON XLAT=0. YLON=0. YLAT=1.0/DLAT END SUBROUTINE EQUID_CYLIND_MAP_JACOB ! SUBROUTINE EQUID_CYLIND_GRID_AREA(RLAT,AREA) !$$$ SUBPROGRAM DOCUMENTATION BLOCK ! ! SUBPROGRAM: EQUID_CYLIND_GRID_AREA GRID BOX AREA FOR ! EQUIDISTANT CYLINDRICAL GRIDS ! ! PRGMMR: GAYNO ORG: W/NMC23 DATE: 2015-01-21 ! ! ABSTRACT: THIS SUBPROGRAM COMPUTES THE GRID BOX AREA FOR ! AN EQUIDISTANT CYLINDRICAL GRID. ! ! PROGRAM HISTORY LOG: ! 2015-01-21 GAYNO INITIAL VERSION ! 2015-09-17 GAYNO RENAME AS "EQUID_CYLIND_GRID_AREA" ! ! USAGE: CALL EQUID_CYLIND_GRID_AREA(RLAT,AREA) ! ! INPUT ARGUMENT LIST: ! RLAT - LATITUDE OF GRID POINT IN DEGREES (REAL) ! ! OUTPUT ARGUMENT LIST: ! AREA - AREA WEIGHTS IN M**2 (REAL) ! ! ATTRIBUTES: ! LANGUAGE: FORTRAN 90 ! !$$$ IMPLICIT NONE REAL, INTENT(IN ) :: RLAT REAL, INTENT( OUT) :: AREA REAL, PARAMETER :: PI=3.14159265358979 REAL, PARAMETER :: DPR=180./PI REAL :: DSLAT, RLATU, RLATD RLATU=MIN(MAX(RLAT+DLAT/2,-90.),90.) RLATD=MIN(MAX(RLAT-DLAT/2,-90.),90.) DSLAT=SIN(RLATU/DPR)-SIN(RLATD/DPR) AREA=RERTH**2*ABS(DSLAT*DLON)/DPR END SUBROUTINE EQUID_CYLIND_GRID_AREA END MODULE GDSWZD_EQUID_CYLIND_MOD