SPTGPMD

The SPTGPMD routine performs a Spherical transform
            from spectral coefficients of scalar fields
            to gradient fields on a Mercator grid.
            The wave-space can be either Triangular or Rhomboidal.
            The wave and grid fields may have general indexing,
            but each wave field is in sequential 'IBM order',
            i.e. with zonal wavenumber as the slower index.
            The Mercator grid is identified by the location
            of its first point and by its respective increments.
            The transforms are all multiprocessed over sector points.
            transform several fields at a time to improve vectorization.
            Subprogram can be called from a multiprocessing environment.
 
USAGE:    CALL SPTGPMD(IROMB,MAXWV,KMAX,MI,MJ,
                       KWSKIP,KGSKIP,NISKIP,NJSKIP,
                       RLAT1,RLON1,DLAT,DLON,WAVE,XM,YM)

   Input arguments:
      IROMB    - INTEGER SPECTRAL DOMAIN SHAPE
                 (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
      MAXWV    - INTEGER SPECTRAL TRUNCATION
      KMAX     - INTEGER NUMBER OF FIELDS TO TRANSFORM.
      MI       - INTEGER NUMBER OF POINTS IN THE FASTER ZONAL DIRECTION
      MJ       - INTEGER NUMBER OF POINTS IN THE SLOWER MERID DIRECTION
      KWSKIP   - INTEGER SKIP NUMBER BETWEEN WAVE FIELDS
                 (DEFAULTS TO (MAXWV+1)*((IROMB+1)*MAXWV+2) IF KWSKIP=0)
      KGSKIP   - INTEGER SKIP NUMBER BETWEEN GRID FIELDS
                 (DEFAULTS TO MI*MJ IF KGSKIP=0)
      NISKIP   - INTEGER SKIP NUMBER BETWEEN GRID I-POINTS
                 (DEFAULTS TO 1 IF NISKIP=0)
      NJSKIP   - INTEGER SKIP NUMBER BETWEEN GRID J-POINTS
                 (DEFAULTS TO MI IF NJSKIP=0)
      RLAT1    - REAL LATITUDE OF THE FIRST GRID POINT IN DEGREES
      RLON1    - REAL LONGITUDE OF THE FIRST GRID POINT IN DEGREES
      DLAT     - REAL LATITUDE INCREMENT IN DEGREES SUCH THAT
                 D(PHI)/D(J)=DLAT*COS(PHI) WHERE J IS MERIDIONAL INDEX.
                 DLAT IS NEGATIVE FOR GRIDS INDEXED SOUTHWARD.
                 (IN TERMS OF GRID INCREMENT DY VALID AT LATITUDE RLATI,
                  THE LATITUDE INCREMENT DLAT IS DETERMINED AS
                  DLAT=DPR*DY/(RERTH*COS(RLATI/DPR))
                  WHERE DPR=180/PI AND RERTH IS EARTH'S RADIUS)
      DLON     - REAL LONGITUDE INCREMENT IN DEGREES SUCH THAT
                 D(LAMBDA)/D(I)=DLON WHERE I IS ZONAL INDEX.
                 DLON IS NEGATIVE FOR GRIDS INDEXED WESTWARD.
      WAVE     - REAL (*) WAVE FIELDS

   Output arguments:
      XM       - REAL (*) MERCATOR X-GRADIENTS
      YM       - REAL (*) MERCATOR Y-GRADIENTS
 
 
SPLIB.tar Library contains routines to be be used for a variety of spectral transform functions. (Fortran90)
Date posted: 2/23/2007