NCL Home > Documentation > Functions > General applied math


Calculates the wavelet transform of a time series and significance levels.


	function wavelet_default (
		y      [*] : numeric,  
		mother [1] : integer   

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



A one-dimensional array (call the length N).


An integer giving the mother wavelet to use:

0 = 'Morlet'
1 = 'Paul'
2 = 'DOG' (derivative of Gaussian)

If mother < 0 or > 2, then the default is 'Morlet'. (Most commonly, mother = 0.)

Return value

This function returns a three-dimensional array (call it wave) dimensioned 2 x jtot x N (see the description below for information on jtot). wave will contain the real (0,:,:) and imaginary parts (1,:,:) of the wavelet transform, versus time and scale. It will be of type double if y is double, and float otherwise.


This function is identical to wavelet, except that it sets some default values for some of the input parameters available to wavelet:

wavelet input parameter default value
dt 1
param 6.0 if mother <= 0 or mother > 2
4.0 if mother = 1
2.0 if mother = 2
s0 2 * dt
dj 0.25
jtot 1 + ((log(N*dt/s0))/dj)/log(2.)
npad dimsizes(y)
noise 1
isigtest 0
siglvl 0.05
nadof currently ignored

Please see the wavelet documentation for a full description of how this function works.