morlet: Perform a Continuous Morlet Wavelet Transform
In dplR: Dendrochronology Program Library in R

Description Usage Arguments Details Value Note Author(s) References See Also Examples

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

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

`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.

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

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.

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

Andy Bunn. Patched and improved by Mikko Korpela.

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

wavelet.plot

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