astrochron (version 0.9)

etp: Generate eccentricity-tilt-precession models

Description

Calculate eccentricity-tilt-precession time series using the theoretical astronomical solutions. By default, the Laskar et al. (2004) solutions will be downloaded. Alternatively, one can specify the astronomical solution.

Usage

etp(tmin=NULL,tmax=NULL,dt=1,eWt=1,oWt=1,pWt=1,esinw=T,solution=NULL,standardize=T,
     genplot=T,verbose=T)

Arguments

tmin

Start time (ka before present, J2000) for ETP. Default value is 0 ka, unless the data frame 'solution' is specified, in which case the first time datum is used.

tmax

End time (ka before present, J2000) for ETP. Default value is 1000 ka, unless the data frame 'solution' is specified, in which case the last time datum is used.

dt

Sample interval for ETP (ka). Minimum = 1 ka.

eWt

Relative weight applied to eccentricity solution.

oWt

Relative weight applied to obliquity solution.

pWt

Relative weight applied to precession solution.

esinw

Use e*sinw in ETP calculation? (T or F). If set to false, sinw is used.

solution

A data frame containing the astronomical solution to use. The data frame must have four columns: Time (ka, positive and increasing), Precession Angle, Obliquity, Eccentricity.

standardize

Standardize (subtract mean, divide by standard deviation) precession, obliquity and eccentricity series before applying weight and combining? (T or F)

genplot

Generate summary plots? (T or F).

verbose

Verbose output? (T or F).

Value

Eccentricity + tilt + precession.

Details

Note: If you plan to repeatedly execute the etp function, it is advisable to download the astronomical solution once using the function getLaskar.

Note: It is common practice to construct ETP models that have specified variance ratios (e.g., 1:1:1 or 1:0.5:0.5) for eccentricity, obliquity and precession. In order to construct such models, it is necessary to choose 'standardize=T', and to set the individual weights (eWt, oWt, pWt) to the square root of the desired variance contribution.

References

Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M., Levrard, B., 2004, A long term numerical solution for the insolation quantities of the Earth: Astron. Astrophys., Volume 428, 261-285.

Laskar, J., Fienga, A., Gastineau, M., Manche, H., 2011, La2010: A new orbital solution for the long-term motion of the Earth: Astron. Astrophys., Volume 532, A89.

Laskar, J., Gastineau, M., Delisle, J.-B., Farres, A., Fienga, A.: 2011, Strong chaos induced by close encounters with Ceres and Vesta: Astron. Astrophys., Volume 532, L4.

See Also

getLaskar

Examples

# NOT RUN {
# create an ETP model from 10000 ka to 20000 ka, with a 5 ka sampling interval
# this will automatically download the astronomical solution
ex=etp(tmin=10000,tmax=20000,dt=5)

# alternatively, download the astronomical solution first
ex2=getLaskar()
ex=etp(tmin=10000,tmax=20000,dt=5,solution=ex2)
# }