The SPLAT routine computes cosines of colatitude and gaussian weights
for one of the following specific global sets of latitudes.
Gaussian latitudes (idrt=4)
Equally-Spaced latitudes including poles (idrt=0)
Equally-Spaced latitudes excluding poles (idrt=256)
The Gaussian latitudes are located at the zeroes of the
legendre polynomial of the given order. These latitudes
are efficient for reversible transforms from spectral space.
(about twice as many equally-spaced latitudes are needed.)
The weights for the equally-spaced latitudes are based on
Ellsaesser (Jan,1966). (No weight is given the pole point.)
note that when analyzing grid to spectral in latitude pairs,
If an equator point exists, its weight should be halved.
This version invokes the IBM ESSL Matrix Solver.
USAGE: CALL SPLAT(IDRT,JMAX,SLAT,WLAT)
Input argument list:
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)
JMAX - INTEGER NUMBER OF LATITUDES.
Output argument list:
SLAT - REAL (JMAX) SINES OF LATITUDE.
WLAT - REAL (JMAX) GAUSSIAN WEIGHTS.
||Library contains routines to be
be used for a variety of spectral transform functions. (Fortran90)
Date posted: 2/23/2007