net | R Documentation |
Computes the \mathit{NET}
parameter for a set of tree-ring
records or other time-series data.
net(x, weights = c(v = 1, g = 1))
x |
A |
weights |
A |
This function computes the \mathit{NET}
parameter (Esper et
al., 2001). The overall \mathit{NET}
is an average of all
(non-NA
) yearly values \mathit{NET_j}
, which are
computed as follows:
\mathit{NET_j}=v_j+(1-G_j)
The yearly variation v_j
is the standard deviation of the
measurements of a single year divided by their mean.
Gegenläufigkeit 1-G_j
is based
on one definition of Gleichläufigkeit
G_j
, similar to but not the same as what glk
computes. Particularly, in the formula used by this function (Esper
et al., 2001), simultaneous zero differences in two series are not
counted as a synchronous change.
The weights of v_j
and 1-G_j
in the sum can
be adjusted with the argument weights
(see above). As a
rather extreme example, it is possible to isolate variation or
Gegenläufigkeit by setting one of the weights
to zero (see ‘Examples’).
A list
with the following components, in the same order as
described here:
all |
a |
average |
a |
Mikko Korpela
Esper, J., Neuwirth, B., and Treydte, K. (2001) A new parameter to evaluate temporal signal strength of tree-ring chronologies. Dendrochronologia, 19(1), 93–102.
library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.net <- net(ca533.rwi)
tail(ca533.net$all)
ca533.net$average
## Not run:
## Isolate the components of NET
ca533.v <- net(ca533.rwi, weights=c(v=1,0))
ca533.g <- net(ca533.rwi, weights=c(g=1,0))
## End(Not run)
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