wcs: Wavelet Sample Cross Spectrum

In Dasonk/SOWAS: Software for Wavelet Analysis and Synthesis

Description

This funtion estimates the wavelet cross spectrum of two time series objects with the Morlet wavelet.

Usage

  wcs(ts1, ts2, s0 = 1, noctave = 5, nvoice = 10,
    w0 = 2 * pi, sw = 0, tw = 0, swabs = 0, markt = -999,
    marks = -999, logscale = FALSE, phase = TRUE,
    plot = TRUE, units = "", device = "screen",
    file = "wcsp", split = FALSE, color = TRUE,
    pwidth = 10, pheight = 7, labsc = 1, labtext = "")

Arguments

ts1	first time series object to be transformed
ts2	second time series object to be transformed
s0	lowest calculated scale in units of the time series
noctave	number of octaves
nvoice	number of voices per octave
w0	time/frequency resolution omega_0
sw	length of smoothing window in scale direction is 2*sw*nvoice+1
tw	length of smoothing window in time direction is 2*s*tw+1
swabs	length of smoothing window in scale direction at scale s is 2*swabs+1
markt	vector of times to be marked by vertical dotted lines; when set to -999 (default), no lines are plotted.
marks	vector of scales to be marked by horizontal dotted lines; when set to -999 (default), no lines are plotted.
logscale	when TRUE, the contours are plotted in logarithmic scale
phase	TRUE when phase calculation desired
plot	TRUE when graphical output desired
units	character string giving units of the data sets. Default: ""
device	"screen" or "ps"
file	character string giving filename of graphical output without extension
split	when TRUE, modulus and phase are splitted into two files; default: FALSE
color	TRUE (default): color plot, FALSE: gray scale
pwidth	width of plot in cm
pheight	height of plot in cm
labsc	scale of labels, default: 1, for two-column manuscripts: 1.5, for presentations: >2
labtext	puts a label in upper left corner of the plot

Details

WARNING! Better do not use this function because it is in general easily misinterpreted! A peak in the wavelet cross sample spectrum appears in the three cases, that either the first processes exhibits a peak, or the second process or both. But it does not tell, what case is observed. So in general, a peak in the wavelet cross sample spectrum does not imply that the two underlying processes are related in any way. The function returns an object of type "wt", that might be directly plotted by the plot function.

Value

modulus matrix of modulus of wavelet sample cross spectrum of dimension [length(intersection of ts1 and ts2)]x[nvoice*noctave+1] phase matrix of phase of wavelet sample cross spectrum, same dimension as modulus s0 lowest calculated scale in units of the time series noctave number of octaves nvoice number of voices per octave w0 time/frequency resolution omega_0 time vector of times of length(intersection of ts1 and ts2) scales vector of scales of length nvoice*noctave+1 critval not used at not used kernel not used

Author(s)

D. Maraun

References

D. Maraun and J. Kurths, Nonlin. Proc. Geophys. 11: 505-514, 2004

See Also

cwt.ts, wsp, wco

Examples

##
data(nao)
data(nino3)

# wcs mimics peaks of coherent power, where in reality are non to be
# found, as wco shows (see FAQs on my homepage)
# Thus, never use wcs! :-)
wcsp.nao.nino3 <- wcs(nao,nino3,s0=0.5,noctave=5,nvoice=10)
wcoh.nao.nino3 <- wco(nao,nino3,s0=0.5,noctave=5,nvoice=10,sw=0.5,arealsiglevel=0)

Dasonk/SOWAS documentation built on May 6, 2019, 1:36 p.m.