pointRes (version 2.0.2)

lowpass13: Apply 13-year low-pass filter

Description

The function applies a 13-year weighted low-pass filter, as described by Fritts (1976), on a data.frame with tree-ring series.

Usage

lowpass13(data)

Value

The function returns a data.frame with 13-year low-pass filtered index series.

Arguments

data

a data.frame with raw tree-ring series as columns and years as rows (e.g., output of read.rwl of package dplR).

Author

Marieke van der Maaten-Theunissen and Ernst van der Maaten.

Details

A 13-year weighted low-pass filter, as described by Fritts (1976, p. 270), can be applied to tree-ring series prior to the calculation of event and pointer years using pointer.norm. According to Cropper (1979), such a filter improves the detection of event and pointer years for complacent series, whereas for sensitive series filtering has little effect.

Note that the resulting time series are truncated by 6 years at both ends inherent to the calculation method.

References

Cropper, J.P. (1979) Tree-ring skeleton plotting by computer. Tree-Ring Bulletin 39: 47-59.

Fritts, H.C. (1976) Tree rings and climate. Academic Press Inc. (London) Ltd.

Examples

data(s033)
lp13_s033 <- lowpass13(s033)