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

In astrochron: A Computational Tool for Astrochronology

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)

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