PerturbCoreSegment: Age perturb proxy core segments

In EarthSystemDiagnostics/simproxyage: Simulate Age Uncertainty in Climate Proxy Records.

Description

PerturbCoreSegment age perturbs the proxy data of an individual segment of a similarly dated core array, i.e. the section of the cores that lies between two specified age control points.

Usage

PerturbCoreSegment(X, t, Xp = array(dim = c(dim(X), ns)), Tp = Xp,
  acp1 = t[1], acp2 = NA, nc = dim(X)[2], ns = 1000,
  model = "poisson", rate = 0.05, resize = 1)

Arguments

X	an nt * nc array of the proxy data from the core array, where the number of rows (nt) is the length of the cores (i.e. the length of the proxy data) and the number of columns (nc) the number of cores in the array.
t	numeric vector providing the original layer-counted chronology. Must equal the length of the proxy data, thus dim(X)[1].
Xp	array of dimension c(dim(X), ns), where ns is the number of age perturbation realisations, to store the perturbed proxy data. To be provided with the calling function.
Tp	array of the same dimension as Xp to store the age perturbation realisations. To be provided with the calling function.
acp1	the first age control point, i.e. the start age at the top of the core segment (per default t[1]).
acp2	the second age control point at the end of the core segment; NA (the default) results in an unconstrained age perturbation process.
nc	integer number of cores in the core array; per default set to the number of columns in X.
ns	integer number of age perturbation realisations for each core.
model	name string of the random process to use for perturbing the age model; must be either "poisson" (the default) or "bernoulli"; see Comboul et al. (2014) for details on the two models.
rate	numeric vector of probability rate(s) that an age band is perturbed; you can specify a vector of two rates where the first entry is the probability for a missing band and the second entry the probability for a double-counting of a band. If only a single value is specified (per default 0.05), symmetric perturbations are assumed.
resize	the resizing option in case of shorter/longer than original time axes: 0 = do not resize, -1 = resize to shortest realisation, 1 = resize to longest realisation (default).

Details

PerturbCoreSegment's intended use is in combination with PerturbCoreArray only rather than as a standalone function (though possible).

Value

A list of two components:

Tp:

The array of age perturbation realisations filled with the realisations corresponding to the time interval between acp1 and acp2.

Xp:

The array of age perturbed proxy data filled with the perturbation realisations corresponding to the time interval between acp1 and acp2.

Author(s)

Thomas Münch

References

Comboul, M., Emile-Geay, J., Evans, M. N., Mirnateghi, N., Cobb, K. M. and Thompson, D. M.: A probabilistic model of chronological errors in layer-counted climate proxies: applications to annually banded coral archives, Clim. Past, 10(2), 825-841, doi: 10.5194/cp-10-825-2014, 2014.

See Also

PerturbCoreArray

EarthSystemDiagnostics/simproxyage documentation built on May 7, 2019, 9:52 p.m.