morlet: Perform a Continuous Morlet Wavelet Transform

In dplR: Dendrochronology Program Library in R

Perform a Continuous Morlet Wavelet Transform

Description

This function performs a continuous wavelet transform on a time series.

Usage

morlet(y1, x1 = seq_along(y1), p2 = NULL, dj = 0.25, siglvl = 0.95)

Arguments

y1	numeric vector. Series to be transformed.
x1	numeric. A vector of values giving the years for the plot. Must be the same length as length(y1).
p2	numeric. The number of power of two to be computed for the wavelet transform. Calculated from length of y1 if NULL.
dj	numeric. Sub-octaves per octave calculated.
siglvl	numeric. Level for the significance test.

Details

This performs a continuous wavelet transform of a time series. This function is typically invoked with wavelet.plot.

Value

A list containing:

y	numeric. The original time series.
x	numeric. The time values.
wave	complex. The wavelet transform.
coi	numeric. The cone of influence.
period	numeric. The period.
Scale	numeric. The scale.
Signif	numeric. The significant values.
Power	numeric. The squared power.

Note

This is a port of Torrence’s IDL code, which can be accessed through the Internet Archive Wayback Machine.

Author(s)

Andy Bunn. Patched and improved by Mikko Korpela.

References

Torrence, C. and Compo, G. P. (1998) A practical guide to wavelet analysis. Bulletin of the American Meteorological Society, 79(1), 61–78.

See Also

wavelet.plot

Examples

library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.crn <- chron(ca533.rwi, prewhiten = FALSE)
Years <- time(ca533.crn)
CAMstd <- ca533.crn[, 1]
out.wave <- morlet(y1 = CAMstd, x1 = Years, dj = 0.1, siglvl = 0.99)

dplR documentation built on June 22, 2024, 9:59 a.m.