eTimeOpt {astrochron}R Documentation

eTimeOpt: Evolutive implementation of TimeOpt (Meyers, 2015; Meyers, 2019)

Description

eTimeOpt: Evolutive implementation of TimeOpt (Meyers, 2015; Meyers, 2019).

Usage

eTimeOpt(dat,win=dt*100,step=dt*10,sedmin=0.5,sedmax=5,numsed=100,linLog=1,
    limit=T,fit=1,fitModPwr=T,flow=NULL,fhigh=NULL,roll=NULL,targetE=NULL,targetP=NULL,
    detrend=T,ydir=1,palette=6,ncolors=100,output=1,genplot=T,check=T,verbose=1)

Arguments

dat

Stratigraphic series for astrochronologic assessment. First column should be depth or height (in meters), second column should be data value.

win

Window size, in meters.

step

Step size for moving window, in meters.

sedmin

Minimum sedimentation rate for investigation (cm/ka).

sedmax

Maximum sedimentation rate for investigation (cm/ka).

numsed

Number of sedimentation rates to investigate in optimization grid.

linLog

Use linear or logarithmic scaling for sedimentation rate grid spacing? (0=linear, 1=log; default value is 1)

limit

Limit evaluated sedimentation rates to region in which full target signal can be recovered? (T or F).

fit

Test for (1) precession amplitude modulation or (2) short eccentricity amplitude modulation?

fitModPwr

Include the modulation periods in the spectral fit? (T or F)

flow

Low frequency cut-off for Taner bandpass (half power point; in cycles/ka)

fhigh

High frequency cut-off for Taner bandpass (half power point; in cycles/ka)

roll

Taner filter roll-off rate, in dB/octave.

targetE

A vector of eccentricity periods to evaluate (in ka). These must be in order of decreasing period, with a first value of 405 ka.

targetP

A vector of precession periods to evaluate (in ka). These must be in order of decreasing period.

detrend

Remove linear trend from data series? (T or F)

ydir

Direction for y-axis in plots (depth,height,time). -1 = values increase downwards (slower plotting), 1 = values increase upwards

palette

What color palette would you like to use? (1) rainbow, (2) grayscale, (3) blue, (4) red, (5) blue-white-red (if values are negative and positive, white is centered on zero), (6) viridis

ncolors

Number of colors steps to use in palette.

output

Which results would you like to return to the console? (0) no output; (1) everything, (2) r^2_envelope, (3) r^2_power, (4) r^2_opt

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? (0=nothing, 1=minimal, 2=a little more, 3=everything!)

References

S.R. Meyers, 2015, The evaluation of eccentricity-related amplitude modulations and bundling in paleoclimate data: An inverse approach for astrochronologic testing and time scale optimization: Paleoceanography, v.30, 1625-1640.

S.R. Meyers, 2019, Cyclostratigraphy and the problem of astrochronologic testing: Earth-Science Reviews v.190, 190-223.

See Also

tracePeak,trackPeak,timeOpt,timeOptSim, and eTimeOptTrack

Examples

## Not run: 
# generate a test signal with precession and eccentricity
ex=cycles(freqs=c(1/405.6795,1/130.719,1/123.839,1/98.86307,1/94.87666,1/23.62069, 
1/22.31868,1/19.06768,1/18.91979),end=4000,dt=5)

# convert to meters with a linearly increasing sedimentation rate from 0.01 m/kyr to 0.03 m/kyr
ex=sedRamp(ex,srstart=0.01,srend=0.03)

# interpolate to median sampling interval
ex=linterp(ex)

# evaluate precession & eccentricity power, and precession modulations
res=eTimeOpt(ex,win=20,step=1,fit=1,output=1)

# extract the optimal fits for the power optimization
sedrates=eTimeOptTrack(res[2])

# extract the optimal fits for the envelope*power optimization
sedrates=eTimeOptTrack(res[3])

# you can also interactively track the results using functions 'trackPeak' and 'tracePeak'
#  evaluate the results from the power optimization
sedrates=tracePeak(res[2])
sedrates=trackPeak(res[2])

#  evaluate the results from the envelope*power optimization
sedrates=tracePeak(res[3])
sedrates=trackPeak(res[3])

# evaluate precession & eccentricity power, and short-eccentricity modulations
eTimeOpt(ex,win=20,step=1,fit=2,output=0)

## End(Not run)

[Package astrochron version 1.1 Index]