Re: Help:question about wavelet

Enver Ramirez wrote:
> Hi everybody,
>
> I was trying to use the wavelet package and I found some dificulties,
> as for example to understand why in the given example the Y-axis of
> the first and second plot are different. I used other data and in
> general numeric values of the y-axis of the second picture are
> different from the first.
This is not clear.

http://www.ncl.ucar.edu/Applications/wavelet.shtml

has two examples. In Example 1 the plots have the same y-axis while
tExample 2
has different Y-axes. The 2nd figures represent differnt things.

>
> I also notice that the lag1 used to determine the theoretical rednoise
> is not a parameter, as it is not given as an argument, so I wonder
> what is the lag1 used in the NCL wavelet package?
It is essentially the same as that returned by:

    http://www.ncl.ucar.edu/Document/Functions/Built-in/esacr.shtml
>
> Another think that I would like to use is cross wavelet analysis, but
> I don´t know is it is implemented yet.

If someone donates the code [C, fortran or NCL] it will be included.
I will not develop it.
>
> And my last question, is there any way to see the source codes of the
> functions implemented in ncl?, as for example: wavelet, specx_anal, ....?
As documented in the wavelet description, the source code
for the wavelet is from:

    http://paos.colorado.edu/research/wavelets/

specx_anal ... I could send you the fortran. It

[a] tapers the data
[b] does an FFT on the taperd data.
[c] computes the periodgram
[d] smooths the periodogram [essentially a running average]
[e] normalize the area under the spectrum to equal the variance
     of the series.

    
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Received on Tue Jul 17 2007 - 15:49:35 MDT