>I have a easy question , I want to get long wave(1-3)
>and short wave(4-) by spatial Fourier decomposition ,
>do NCL have a function can do this?
>x(lat ,lon)---> xwave
>Thanks for any suggestion!
-- Yes, of course. One approach is to use the FFT routines: ezfftf, ezfftb (Missing data are not allowed.)
See Example 3
-- nLong = 3 xLong = x xShort = x
ab = ezfftf(x) xLong = ezfftb(ab(:,0:nLong-1), 0.0) ; total amplitude (1-3) xLong@long_name = "Long Waves" xShort = ezfftb(ab(:,nLong: ), 0.0) ; total amplitude (4-nlon/2) xShort@long_name = "Short Waves"
Youc could also try the spherical harmonic analysis/synthesis family of functions "sha*" and "shs*"
good luck D
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