etp {astrochron} | R Documentation |
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). |
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.
Value
Eccentricity + tilt + precession.
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
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)
## End(Not run)