Spectrum: Estimates Frequency Spectrum

In s2dverification: Set of Common Tools for Forecast Verification

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 an array 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)

Arguments

xdata

Array of which the frequency spectrum is required.

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.

Author(s)

History:
0.1 - 2012-02 (V. Guemas) - Original code
1.0 - 2013-09 (N. Manubens) - Formatting to CRAN

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')
 

s2dverification documentation built on April 20, 2022, 9:06 a.m.