R: Perform a Continuous Morlet Wavelet Transform

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.

### See Also

`wavelet.plot`

### Examples

    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)

[Package dplR version 1.7.1 Index]