mergespec: Spectral merging of a coarse field and of a fine field at a...
In rainfarmr: Stochastic Precipitation Downscaling with the RainFARM Method

Description Usage Arguments Value Author(s) Examples

The input fields are transformed to Fourier space, their Fourier spectra are merged at wavenumber kmax after adapting the variance of the fine field and an inverse Fourier transform is performed.

1	mergespec(ra, r, kmax = 0)

`ra`	matrix containing a coarse field of size `c(nas, nas)`.
`r`	matrix containing a field at higher resolution.
`kmax`	wavenumber to use for merging (default `nas/2`).

The merged field, in physical space.

Jost von Hardenberg, j.vonhardenberg@isac.cnr.it

# Make a coarse field with power-law Fourier spectrum 
fa <- initmetagauss(1.7, 8)
ra <- metagauss(fa)
# Make a fine power-law Fourier spectrum
f <- initmetagauss(1.7, 32)
r <- metagauss(f)
# Merge the two fields in spectral space
rm <- mergespec(ra, r, kmax = 4)
# Check spectral slope of the resulting field
fx <- fft2d(rm)
fitslope(fx)
# 1.678554