taner: Apply Taner bandpass or lowpass filter to stratigraphic...

In astrochron: A Computational Tool for Astrochronology

Apply Taner bandpass or lowpass filter to stratigraphic series

Description

Apply Taner bandpass or lowpass filter to stratigraphic series. This function can also be used to notch filter or highpass a record (see examples).

Usage

taner(dat,padfac=2,flow=NULL,fhigh=NULL,roll=10^3,demean=T,detrend=F,addmean=T,
       output=1,xmin=0,xmax=Nyq,genplot=T,check=T,verbose=T)

Arguments

dat	Stratigraphic series for bandpass filtering. First column should be location (e.g., depth), second column should be data value.
padfac	Pad with zeros to (padfac*npts) points, where npts is the original number of data points.
flow	Low frequency cut-off for Taner filter (half power point). If this value is not set (NULL), it will default to -1*fhigh, which will create a lowpass filter.
fhigh	High frequency cut-off for Taner filter (half power point).
roll	Roll-off rate, in dB/octave. Typical values are 10^3 to 10^12, but can be larger.
demean	Remove mean from data series? (T or F)
detrend	Remove linear trend from data series? (T or F)
addmean	Add mean value to bandpass result? (T or F)
output	Output: (1) filtered series, (2) bandpass filter window.
xmin	Smallest frequency for plotting.
xmax	Largest frequency for plotting.
genplot	Generate summary plots? (T or F)
check	Conduct compliance checks before processing? (T or F) In general this should be activated; the option is included for Monte Carlo simulation.
verbose	Verbose output? (T or F)

Value

bandpassed stratigraphic series.

References

http://www.rocksolidimages.com/pdf/attrib_revisited.htm#_Toc328470897

See Also

bandpass, lowpass, noKernel, noLow, prewhiteAR, and prewhiteAR1

Examples

# generate example series with periods of 405 ka, 100 ka, 40ka, and 20 ka, plus noise
ex=cycles(freqs=c(1/405,1/100,1/40,1/20),end=1000,dt=5,noisevar=.1)

# bandpass precession term using Taner window 
bandpass_ex <- taner(ex,flow=0.045,fhigh=0.055,roll=10^10)

# lowpass filter eccentricity terms using Taner window
lowpass_ex=taner(ex,fhigh=.02,roll=10^10)

# notch filter (remove) obliquity term using Taner window
#  if you'd like the final notch filtered record to be centered on the mean proxy 
#  value, set addmean=FALSE
notch_ex <- taner(ex,flow=0.02,fhigh=0.03,roll=10^10,addmean=FALSE)
notch_ex[2] <- ex[2]-notch_ex[2]
pl(2)
plot(ex,type="l",main="Eccentricity+Obliquity+Precession")
plot(notch_ex,type="l",main="Following application of obliquity notch filter")

# highpass filter obliquity and precession terms using Taner window
#  if you'd like the final highpass filtered record to be centered on the mean proxy 
#  value, set addmean=FALSE
highpass_ex=taner(ex,fhigh=.02,roll=10^10,addmean=FALSE)
highpass_ex[2] <- ex[2]-highpass_ex[2]
pl(2)
plot(ex,type="l",main="Eccentricity+Obliquity+Precession")
plot(highpass_ex,type="l",main="Obliquity+Precession highpassed signal")

astrochron documentation built on Sept. 30, 2024, 9:14 a.m.