ProxyErrorSpectrum: Power Spectral Density of the Error in a Sediment Archived...

In EarthSystemDiagnostics/psem: Proxy Spectral Error Model

Power Spectral Density of the Error in a Sediment Archived Proxy Timeseries

Description

Power Spectral Density of the Error in a Sediment Archived Proxy Timeseries

Usage

ProxyErrorSpectrum(
  nu = NULL,
  tau_s,
  tau_b,
  tau_p,
  tau_r,
  T,
  delta_t,
  N,
  n.k,
  clim.spec.fun,
  clim.spec.fun.args,
  sig.sq_a,
  sig.sq_c,
  nu_a,
  nu_c,
  phi_a,
  phi_c,
  delta_phi_c,
  sigma.meas,
  sigma.ind,
  sigma.cal,
  n.nu.prime = 1000,
  ...
)

Arguments

nu	frequency
tau_s	sediment slice thickness in years (layer.width / sedimentation rate)
tau_b	timescale of bioturbation (bioturbation depth / sedimentation rate) (L/sr)
tau_p	length of proxy carrier "growth season" (< 12 months)
tau_r	width of moving average filter that represents the "interpreted" resolution of the timeseries
T	length of a finite time series, e.g. 1e04
delta_t	sampling frequency of the sediment core / climate timeseries
N	number of signal carriers (e.g. individual foraminifera)
n.k	the number of aliasers used when estimating the error spectrum of the stochastic climate signal. Defaults to 15, does not normally need to be adjusted.
clim.spec.fun	a function to return climate power spectral density as a function of frequency, nu
clim.spec.fun.args	arguments to the named climate power spectrum function
sig.sq_a	variance of precessionary amplitude modulation
sig.sq_c	variance of the seasonal cycle
nu_a	1/tau_a = frequency of the orbital variation, e.g. for precession 1/23e03 yrs
nu_c	1/1 (yr) = frequency of the seasonal cycle
phi_a	phase of precessionary amplitude modulation relative to centre of finite timeseries of length T
phi_c	phase of carrier growth season relative to the maximum of the seasonal cycle
delta_phi_c	Uncertainty in the phase of the signal carrier production. A value between 0 and 2Pi.
sigma.meas	the standard deviation of the per sample measurement error
sigma.ind	the standard deviation of error between individuals (e.g. foraminifera) e.g. due to "vital effects" or calcification depth
sigma.cal	the 1-sigma (standard deviation) of the calibration error in the same units as the proxy
n.nu.prime	number of discrete frequencies at which to evaluate the PSD of the error

Value

a dataframe of frequencies and spectral power

Examples

spec.pars <- GetSpecPars("Mg_Ca", tau_p = 4 / 12, delta_phi_c = pi)
spec.obj <- do.call(ProxyErrorSpectrum, spec.pars)
PlotSpecError(spec.obj)

EarthSystemDiagnostics/psem documentation built on March 3, 2024, 10:24 p.m.