[ncl-talk] Spectral Analysis (Period in X-axis)

[S. B. Ratna]

Hi All,
I would like to plot the spectral analysis for my annual mean data for
about 800 years. I would like to use 'spec_4.ncl' but I need "period
(year)" in the X-axis instead of "Frequency".
Also, the X-axis scale should be 4 8 16 32 64 128 256 512.
Could you please suggest how to draw such figure.
https://www.ncl.ucar.edu/Applications/Scripts/spec_4.ncl

Thanks.
SBR