morlet {dplR} R Documentation

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.

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)


[Package dplR version 1.7.6 Index]