dplR (version 1.4.9)

glk: Calculation of Gleichlaeufigkeit

Description

This function calculates the matrix of Gleichlaeufigkeit for a given set of tree-ring records.

Usage

glk(x)

Arguments

x

a data.frame of tree-ring data with records in columns, and years as rows.

Value

• A matrix with the Gleichlaeufigkeit for all possible combinations of records. If two curves have less than 3 years of overlap, Gleichlaeufigkeit cannot be computed, and NA is returned.

Details

Gleichlaeufigkeit is a classical agreement test based on sign tests (Eckstein and Bauch, 1969). This function implements Gleichlaeufigkeit as the pairwise comparison of all records in data set, and thus returns a matrix whose upper triangle reports the Gleichlaeufigkeit of each possible combination of records. The global Gleichlaeufigkeit can be calculated as mean(glk(x), na.rm = TRUE).

References

Eckstein, D., Bauch J. (1969) Beitrag zur Rationalisierung eines dendrochronologischen Verfahrens und zur Analyse seiner Aussagesicherheit Forstwissenschaftliches Centralblatt 88:230-250.

Schweingruber, F.H. (1988) Tree rings: basics and applications of dendrochronology Kluwer Academic Publishers, Dordrecht, Netherlands, 276 p.

Examples

data(ca533)
ca533.glk <- glk(ca533)
mean(ca533.glk, na.rm = TRUE)