[ncl-talk] vertical wavenumber FFT

[Maria Gehne - NOAA Affiliate]

Hi Chang,

the function ezfftf should do that.

https://www.ncl.ucar.edu/Document/Functions/Built-in/ezfftf.shtml

It works for multidimensional arrays as well as one dimensional arrays, for
more than one dimension you need to reorder so that the pressure levels are
the right most dimension. So if x = (time,lev,lat,lon) you may need to
transform y = x(time,lat,lon,lev).

As with all FFT applications you probably need to taper the values you are
trying to transform so that the end points are zero and you are essentially
transforming a periodic sequence.

Hope this helps,

Maria

On Sun, Feb 15, 2015 at 3:35 PM, Xi Chang <xi.chang01 at gmail.com> wrote:

> Hallo NCL,
>
> is there any trick or function in ncl to decompose the data in pressure
> level to vertical wavenumber (m) based on FFT filter?
>
> Thank you
> Chang
>
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