sptrung.f File Reference

Spectrally interpolate scalars to stations. More...

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Functions/Subroutines
subroutine	sptrung (iromb, maxwv, idrti, imaxi, jmaxi, kmax, nmax, iprime, iskipi, jskipi, kskipi, kgskip, nrskip, ngskip, jcpu, rlat, rlon, gridi, gp)
	This subprogram spectrally truncates scalar fields on a global cylindrical grid, returning the fields to specified sets of station points on the globe.

Detailed Description

Spectrally interpolate scalars to stations.

Author

IREDELL

Date

96-02-29

Definition in file sptrung.f.

Function/Subroutine Documentation

sptrung()

subroutine sptrung	(		iromb,
			maxwv,
			idrti,
			imaxi,
			jmaxi,
			kmax,
			nmax,
			iprime,
			iskipi,
			jskipi,
			kskipi,
			kgskip,
			nrskip,
			ngskip,
			jcpu,
		real, dimension(*)	rlat,
		real, dimension(*)	rlon,
		real, dimension(*)	gridi,
		real, dimension(*)	gp
	)

This subprogram spectrally truncates scalar fields on a global cylindrical grid, returning the fields to specified sets of station points on the globe.

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. The grid and point fields may have general indexing. The transforms are all multiprocessed. Transform several fields at a time to improve vectorization. Subprogram can be called from a multiprocessing environment.

Parameters

	IROMB	- INTEGER SPECTRAL DOMAIN SHAPE (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
	MAXWV	- INTEGER SPECTRAL TRUNCATION
	IDRTI	- INTEGER INPUT GRID IDENTIFIER (IDRTI=4 FOR GAUSSIAN GRID, IDRTI=0 FOR EQUALLY-SPACED GRID INCLUDING POLES, IDRTI=256 FOR EQUALLY-SPACED GRID EXCLUDING POLES)
	IMAXI	- INTEGER EVEN NUMBER OF INPUT LONGITUDES.
	JMAXI	- INTEGER NUMBER OF INPUT LATITUDES.
	KMAX	- INTEGER NUMBER OF FIELDS TO TRANSFORM.
	NMAX	- INTEGER NUMBER OF STATION POINTS TO RETURN
	IPRIME	- INTEGER INPUT LONGITUDE INDEX FOR THE PRIME MERIDIAN. (DEFAULTS TO 1 IF IPRIME=0) (OUTPUT LONGITUDE INDEX FOR PRIME MERIDIAN ASSUMED 1.)
	ISKIPI	- INTEGER SKIP NUMBER BETWEEN INPUT LONGITUDES (DEFAULTS TO 1 IF ISKIPI=0)
	JSKIPI	- INTEGER SKIP NUMBER BETWEEN INPUT LATITUDES FROM SOUTH (DEFAULTS TO -IMAXI IF JSKIPI=0)
	KSKIPI	- INTEGER SKIP NUMBER BETWEEN INPUT GRID FIELDS (DEFAULTS TO IMAXI*JMAXI IF KSKIPI=0)
	KGSKIP	- INTEGER SKIP NUMBER BETWEEN STATION POINT SETS (DEFAULTS TO NMAX IF KGSKIP=0)
	NRSKIP	- INTEGER SKIP NUMBER BETWEEN STATION LATS AND LONS (DEFAULTS TO 1 IF NRSKIP=0)
	NGSKIP	- INTEGER SKIP NUMBER BETWEEN STATION POINTS (DEFAULTS TO 1 IF NGSKIP=0)
	RLAT	- REAL (*) STATION LATITUDES IN DEGREES
	RLON	- REAL (*) STATION LONGITUDES IN DEGREES
	JCPU	- INTEGER NUMBER OF CPUS OVER WHICH TO MULTIPROCESS (DEFAULTS TO ENVIRONMENT NCPUS IF JCPU=0)
	GRIDI	- REAL (*) INPUT GRID FIELDS
[out]	GP	- REAL (*) STATION POINT SETS

SUBPROGRAMS CALLED:

• sptran() Perform a scalar spherical transform
• sptgpt() Transform spectral scalar to station points
• ncpus() Gets environment number of cpus

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 65 of file sptrung.f.

References ncpus(), sptgpt(), and sptran().

Referenced by spectral_interp_mod::polates4::polates4_grib1(), and spectral_interp_mod::polates4::polates4_grib2().