fitslope {rainfarmr}

Compute logarithmic slope of a spatial power spectrum

Description

Uses a linear fit to derive the log-log slope of a Fourier power spectrum.

Usage

fitslope(fx, kmin = 1, kmax = length(fx))

Arguments

fx

vector containing input power spectrum starting from k=1.

kmin

minimum wavenumber for logarithmic fit range.

kmax

maximum wavenumber for logarithmic fit range.

Value

The spatial spectral slope minus one. The slope is returned as the logarithmic slope of k*|A(k)|^2 where |A(k)|^2 are the squared spectral amplitudes provided in input..

Author(s)

Jost von Hardenberg, [e-mail]

Examples

# Make a synthetic rainfall field with prescribed logarithmic spectral slope
f = initmetagauss(1.7, 64)
r = metagauss(f)
# Check spectral slope of the resulting field
fx <- fft2d(r)
print(fitslope(fx))
# 1.640373