s2dverification (version 2.4.0)

Spectrum: Estimates Frequency Spectrum

Description

This function estimates the frequency spectrum of the xdata array together with its 95% and 99% significance level. The output is provided as a matrix with dimensions c(number of frequencies, 4). The column contains the frequency values, the power, the 95% significance level and the 99% one. The spectrum estimation relies on a R built-in function and the significance levels are estimated by a Monte-Carlo method.

Usage

Spectrum(xdata)

Value

Frequency spectrum with dimensions c(number of frequencies, 4). The column contains the frequency values, the power, the 95% significance level and the 99% one.

Examples

# Load sample data as in Load() example:
example(Load)

ensmod <- Mean1Dim(sampleData$mod, 2)
for (jstartdate in 1:3) {
  spectrum <- Spectrum(ensmod[1, jstartdate, ])
  for (jlen in 1:dim(spectrum)[1]) {
    if (spectrum[jlen, 2] > spectrum[jlen, 4]) {
      ensmod[1, jstartdate, ] <- Filter(ensmod[1, jstartdate, ],  
                                        spectrum[jlen, 1])
    }
  }
}
PlotAno(InsertDim(ensmod, 2, 1), sdates = startDates, fileout =
        'filtered_ensemble_mean.eps')