Performs inverse spectral transformation by successively carrying out SHTS2W and SHTW2G.
The definitions of ISW and arrays S, W, and G are the same as for SHTS2W and SHTW2G. This routine successively carries out SHTS2W and SHTW2G, with the following results.
When ISW=0, a normal inverse spectral transformation is carried out.
(4.25)
When ISW=1, the latitudinal derivative of the inverse spectral transform is calculated.
(4.26)
When ISW=-1, the meridional derivative of the inverse spectral transform is calculated.
(4.27)
SHTS2G(MM,JM,IM,ISW,S,W,G,WORK)
MM (I) Input parameter. The cut-off wavenumber (M). JM (I) Input parameter. 1/2 of the NS partition number (J) IM (I) Input parameter. 1/2 of the EW partition number (I) ISW (I) Input parameter. Specifies the type of transformation. (See above definition.) S (R) Input parameter. Spectral data. (For length and arrangement, see SHTNML.) W (R) Output parameter. Wave data. (For length and arrangement, see SHTS2W.) G (R) Output parameter. Grid data. (For length and arrangement, see SHTW2G.) WORK (R) Working area initialized by SHTINT.
- (a)
- This subroutine is equivalent to successively calling SHTS2W and SHTW2G.
- (b)
- By using the two transforms for ISW=1 and ISW=-1, it is possible to calculate the gradient vector of a scalar field.