Layer-Counted Proxy Records Uncertainties

Represents layer-counted proxy records as sequences of probability distributions on absolute, error-free time axes.

Usage

proxy_ensemble(positions, ...)

# S4 method for class 'numeric'
proxy_ensemble(
  positions,
  proxy_values,
  proxy_errors,
  proxy_step,
  time_values,
  time_errors,
  calendar,
  from = NULL,
  to = NULL,
  by = NULL,
  n = 30,
  progress = getOption("ananke.progress"),
  verbose = getOption("ananke.verbose")
)

Arguments

positions: A positive numeric vector giving the positions (e.g. depths) at which proxy values and calendar ages were measured. In the case of layers of non-zero thickness, this should be the middle value of the slice. It must be in decreasing order (i.e. in chronological order).
...: Currently not used.
proxy_values: A numeric vector giving the proxy values.
proxy_errors: A numeric vector giving the proxy uncertainties.
proxy_step: A length-one numeric vector specifying the step size (in units of proxy_values) at which proxy records densities are to be estimated.
time_values: A numeric vector giving the calendar ages (in years).
time_errors: A numeric vector giving the calendar age uncertainties (in years).
calendar: An aion::TimeScale object specifying the calendar of time (see aion::calendar()).
from: A length-one numeric vector specifying the starting value of the temporal sequence at which densities are to be estimated (in years).
to: A length-one numeric vector specifying the end value of the temporal sequence at which densities are to be estimated (in cal BP years).
by: A length-one numeric vector specifying the increment of the temporal sequence at which densities are to be estimated (in years).
n: An integer specifying the number of item to choose randomly.
progress: A logical scalar: should a progress bar be displayed?
verbose: A logical scalar: should extra information be reported?

Value

A ProxyRecord object.

Note

This function is currently experimental.

References

Boers, N., Goswami, B. & Ghil, M. (2017). A Complete Representation of Uncertainties in Layer-Counted Paleoclimatic Archives. Climate of the Past, 13(9): 1169-1180. doi:10.5194/cp-13-1169-2017 .

Author

N. Frerebeau

Examples

# \donttest{
## Get NGRIP records
data("ngrip2010", package = "folio")
ngrip2010 <- subset(ngrip2010, !is.na(MCE))
ngrip2010 <- ngrip2010[nrow(ngrip2010):1, ] # Sort in chronological order

## Replicate fig. 3d from Boers et al. (2017)
## /!\ This may take a while... /!\
ngrip_record <- proxy_ensemble(
  positions = ngrip2010$depth,
  proxy_values = ngrip2010$delta,
  proxy_errors = 0.01,
  proxy_step = 0.01,
  time_values = ngrip2010$age,
  time_errors = ngrip2010$MCE,
  calendar = b2k(), # /!\
  by = 20,
  n = 30
)

plot(ngrip_record)

# }