dplR: chron – R documentation

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chron

Build Mean Value Chronology

Description

This function builds a mean value chronology, typically from a data.frame of detrended ring widths as produced by detrend.

Usage

chron(x, prefix = "xxx", biweight = TRUE, prewhiten = FALSE, ...)

Arguments

`x`	a `data.frame` of ring widths with `rownames(x)` containing years and `colnames(x)` containing each series ID such as produced by `read.rwl`
`prefix`	a `character` string with less than 4 characters. Defaults to `"xxx"`
`biweight`	`logical` flag. If TRUE then a robust mean is calculated using `tbrm.`
`prewhiten`	`logical` flag. If TRUE each series is whitened using `ar` prior to averaging.
`...`	Arguments passed to `ar` when `prewhiten` is `TRUE`. For example, use `aic` and `order.max` to control the order of the AR model.

Details

This either averages the rows of the data.frame using a mean or a robust mean (the so-called standard chronology) or can do so from the residuals of an AR process (the residual chronology).

Value

A data.frame with the standard chronology, residual chronology (if prewhitening was performed), and the sample depth.

Author(s)

Andy Bunn. Patched and improved by Mikko Korpela.

References

Cook, E. R. and Kairiukstis, L. A., editors (1990) Methods of Dendrochronology: Applications in the Environmental Sciences. Springer. ISBN-13: 978-0-7923-0586-6.

Fritts, H. C. (2001) Tree Rings and Climate. Blackburn. ISBN-13: 978-1-930665-39-2.

Examples

library(graphics)
library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.crn <- chron(ca533.rwi, prefix = "CAM")
plot(ca533.crn,xlab="Year",ylab="RWI")
## With residual chron
ca533.crn <- chron(ca533.rwi, prefix = "CAM", prewhiten = TRUE)

dplR

Dendrochronology Program Library in R

v1.7.2

GPL (>= 2)

Authors

Andy Bunn [aut, cph, cre, trl], Mikko Korpela [aut, cph, trl], Franco Biondi [aut, cph], Filipe Campelo [aut, cph], Pierre Mérian [aut, cph], Fares Qeadan [aut, cph], Christian Zang [aut, cph], Allan Buras [ctb], Jacob Cecile [ctb], Manfred Mudelsee [ctb], Michael Schulz [ctb], Klesse Stefan [ctb], Frank David [ctb], Visser Ronald [ctb]

Initial release

2021-01-27