NCEPLIBS-sp  2.3.3
sptezm.f File Reference

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Functions/Subroutines

subroutine sptezm (IROMB, MAXWV, IDRT, IMAX, JMAX, KMAX, WAVE, GRID, IDIR)
 THIS SUBPROGRAM PERFORMS SPHERICAL TRANSFORMS BETWEEN SPECTRAL COEFFICIENTS OF SCALAR QUANTITIES AND FIELDS ON A GLOBAL CYLINDRICAL GRID. More...
 

Detailed Description

Perform simple scalar spherical transforms

Author
IREDELL
Date
96-02-29

Definition in file sptezm.f.

Function/Subroutine Documentation

◆ sptezm()

subroutine sptezm (   IROMB,
  MAXWV,
  IDRT,
  IMAX,
  JMAX,
  KMAX,
real, dimension((maxwv+1)*((iromb+1)*maxwv+2),kmax)  WAVE,
real, dimension(imax,jmax,kmax)  GRID,
  IDIR 
)

THIS SUBPROGRAM PERFORMS SPHERICAL TRANSFORMS BETWEEN SPECTRAL COEFFICIENTS OF SCALAR QUANTITIES AND FIELDS ON A GLOBAL CYLINDRICAL GRID.

THE WAVE-SPACE CAN BE EITHER TRIANGULAR OR RHOMBOIDAL. THE GRID-SPACE CAN BE EITHER AN EQUALLY-SPACED GRID (WITH OR WITHOUT POLE POINTS) OR A GAUSSIAN GRID. WAVE FIELDS ARE IN SEQUENTIAL 'IBM ORDER'. GRID FIELDS ARE INDEXED EAST TO WEST, THEN NORTH TO SOUTH. FOR MORE FLEXIBILITY AND EFFICIENCY, CALL SPTRAN. SUBPROGRAM CAN BE CALLED FROM A MULTIPROCESSING ENVIRONMENT.

Parameters
IROMB- INTEGER SPECTRAL DOMAIN SHAPE (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
MAXWV- INTEGER SPECTRAL TRUNCATION
IDRT- INTEGER GRID IDENTIFIER (IDRT=4 FOR GAUSSIAN GRID, IDRT=0 FOR EQUALLY-SPACED GRID INCLUDING POLES, IDRT=256 FOR EQUALLY-SPACED GRID EXCLUDING POLES)
IMAX- INTEGER EVEN NUMBER OF LONGITUDES
JMAX- INTEGER NUMBER OF LATITUDES
KMAX- INTEGER NUMBER OF FIELDS TO TRANSFORM
[out]WAVE- REAL (2*MX,KMAX) WAVE FIELD IF IDIR>0 WHERE MX=(MAXWV+1)*((IROMB+1)*MAXWV+2)/2
[out]GRID- REAL (IMAX,JMAX,KMAX) GRID FIELD (E->W,N->S) IF IDIR<0
IDIR- INTEGER TRANSFORM FLAG (IDIR>0 FOR WAVE TO GRID, IDIR<0 FOR GRID TO WAVE)

SUBPROGRAMS CALLED:

  • SPTRANF PERFORM A SCALAR SPHERICAL TRANSFORM
  • NCPUS GETS ENVIRONMENT NUMBER OF CPUS

REMARKS: MINIMUM GRID DIMENSIONS FOR UNALIASED TRANSFORMS TO SPECTRAL:

DIMENSION LINEAR QUADRATIC
IMAX 2*MAXWV+2 3*MAXWV/2*2+2
JMAX (IDRT=4,IROMB=0) 1*MAXWV+1 3*MAXWV/2+1
JMAX (IDRT=4,IROMB=1) 2*MAXWV+1 5*MAXWV/2+1
JMAX (IDRT=0,IROMB=0) 2*MAXWV+3 3*MAXWV/2*2+3
JMAX (IDRT=0,IROMB=1) 4*MAXWV+3 5*MAXWV/2*2+3
JMAX (IDRT=256,IROMB=0) 2*MAXWV+1 3*MAXWV/2*2+1
JMAX (IDRT=256,IROMB=1) 4*MAXWV+1 5*MAXWV/2*2+1

Definition at line 48 of file sptezm.f.