rwl.stats {dplR}

Calculate Descriptive Summary Statistics on Ring-Width Series

Description

This function calculates descriptive statistics on a rwl object of raw or detrended ring-width series.

Usage

rwl.stats(rwl)

## S3 method for class 'rwl'
summary(object, ...)

Arguments

rwl, object

a rwl object with (usually) raw ring-width series as columns and years as rows such as that produced by read.rwl. It is sometimes desirable to run this on detrended (e.g., rwi) data.

...

Additional arguments from the generic function. These are silently ignored.

Details

This calculates a variety of descriptive statistics commonly used in dendrochronology (see below). Users unfamiliar with these should see Cook and Kairiukstis (1990) and Fritts (2001) for further details.

The summary method for class "rwl" is a wrapper for rwl.stats.

Value

A data.frame containing descriptive stats on each "series". These are the first and last year of the series as well as the length of the series ("first", "last", "year"). The mean, median, standard deviation are given ("mean", "median", "stdev") as are the skewness, the Gini coefficient, and first order autocorrelation ("skew", "gini.coef", "ar1").

Note that prior to version 1.6.8, two measures of sensitivity were also included. However mean sensitivity is not a robust statistic that should rarely, if ever, be used (Bunn et al. 2013). Those sensitivity functions ("sens1" and "sens2") are still available for continuity. Users should consider the coef of variation in lieu of mean sensitivity.

Author(s)

Andy Bunn. Slightly improved by Mikko Korpela.

References

Bunn, A. G., Jansma, E., Korpela, M., Westfall, R. D., and Baldwin, J. (2013) Using simulations and data to evaluate mean sensitivity (\zeta) as a useful statistic in dendrochronology. Dendrochronologia, 31(3), 250–254.

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.

See Also

rwi.stats, read.rwl

Examples

library(utils)
data(ca533)
rwl.stats(ca533)
summary(ca533)