
This function builds a mean value chronology, typically from a
data.frame
of detrended ring widths as produced by
detrend
.
chron(x, biweight = TRUE, prewhiten = FALSE, ...)
An object of of class crn
and data.frame
with the standard chronology, residual chronology (if prewhitening was performed), and the sample depth. The years are stored as row numbers.
a data.frame
of (usually detrended) ring widths with
rownames(x)
containing years and colnames(x)
containing each series ID such as produced by
read.rwl
logical
flag. If TRUE then a robust
mean is calculated using tbrm.
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.
Andy Bunn. Patched and improved by Mikko Korpela.
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).
Note that the residual chronology in this function will return different
values than the residual chronology from chron.ars
which uses
a slightly different method for determining AR order.
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.
read.rwl
, detrend
,
ar
, crn.plot
library(graphics)
library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.crn <- chron(ca533.rwi)
plot(ca533.crn,xlab="Year",ylab="RWI")
## With residual chron
ca533.crn2 <- chron(ca533.rwi, prewhiten = TRUE)
plot(ca533.crn2,xlab="Year",ylab="RWI")
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