# [ncl-talk] Problem plotting wavelet from a time series

Buzan, Jonathan jbuzan at purdue.edu
Fri Oct 1 02:41:37 MDT 2021

```Hi Lyndz,

I believe going back to the wavelet function is your best bet. The examples are there to help guide your decision making, but the actual function explicitly tells the user what each component executes.

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

Prototype

function wavelet (
y        [*] : numeric,
mother   [1] : integer,
dt       [1] : numeric,
param    [1] : numeric,
s0       [1] : numeric,
dj       [1] : numeric,
jtot     [1] : integer,
noise    [1] : integer,
isigtest [1] : integer,
siglvl   [1] : numeric,
)

return_val [2][jtot][dimsizes(y)] :  float or double

…

dt
The amount of time between each y value; i.e. the sampling time. (Most commonly, dt = 1.0.)

Cheers,
-Jonathan

On Oct 1, 2021, at 10:36 AM, Lyndz via ncl-talk <ncl-talk at mailman.ucar.edu<mailto:ncl-talk at mailman.ucar.edu>> wrote:

Dear NCL-experts,

I would like to plot the wavelet from a daily time series (40 summers; 121 days)
X axis is years and Y axis is Period (days).

The examples on the web page appear to be for one value per year only.

I attached the sample data to this email and the script from here:
https://www.ncl.ucar.edu/Applications/wavelet.shtml

I encounter this error:
fatal:NclOneDValGetRangeIndex: Non-monotonic coordinate value being used, can't complete coordinate subscript
fatal:Could not obtain coordinate indexes, unable to perform subscript
fatal:["Execute.c":8637]:Execute: Error occurred at or near line 92 in file wavelet.ncl

I would like to ask, what values should I put in these lines (for the power() and sig():

plot(0) = gsn_csm_contour(wks,power({0:43},0:121),res)
plot(1) = gsn_csm_contour(wks,SIG({0:43},0:121),res)

Is it correct to specify dt = 122 for the wavelet function?

I'll appreciate any help on this.

Sincerely,
Lyndz

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