Re: Unit of variance in spectral analysis

As noted in the function documentation:
    http://www.ncl.ucar.edu/Document/Functions/Built-in/specx_anal.shtml

=======
These spectra have been normalized so that the area under the curve:

     (spcx(0)+spcx(N/2-1))*(df/2) + SUM{spcx(1:N/2-2)*df}

equals the variance of the detrended series, where df=(1/N)=frequency
spacing.

The units are variance/(unit frequency interval).
==========

On 1/15/13 10:23 AM, Hyacinth Nnamchi wrote:
>
> Hi users,
> The vertical axis of the spectral analysis examples (http://www.ncl.ucar.edu/Applications/spec.shtml) are labelled "variance". What is the unit? I'd think it represents the relative contributions of the different frequencies to the overall variance of the time series. But how is it scaled in ncl, as percents?
> Thanks in advance.
> Hyacinth
>
>
>
>
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Received on Tue Jan 15 10:32:57 2013