
NCL Home >
Documentation >
Functions >
Spherical harmonic routines
tri_trunC
Performs triangular truncation on spherical harmonic coefficients.
Prototype
function tri_trunC ( ab : numeric, T : integer ) return_val [dimsizes(ab)] : float or double
Arguments
abSpherical harmonic coefficients returned to user by the NCL functions shagC/shaeC. The first dimension must be 2, which addresses the real and imaginary parts.
T
Triangular truncation parameter. T is the constant number of total wave numbers to keep.
Return value
A double array is returned if the input is double; otherwise a float array is returned. The returned array will be of size dimsizes(ab).
Description
tri_trunC performs triangular truncation on coefficients returned by the Spherepack analysis routines shagC or shaeC.
See Also
tri_trunc, rhomb_trunC, rhomb_trunc, shagC, shsgC shaeC, shseC
Examples
Example 1
g(nlat,nlon)
T = 42 ab = shagC (g) ab = tri_trunC (ab,T) g = shsgC (ab,nlon)