ar1etp {astrochron} | R Documentation |

## AR(1) + ETP simulation routine

### Description

Simulate a combined AR(1) + ETP signal, plot spectrum and confidence levels

### Usage

```
ar1etp(etpdat=NULL,nsim=100,rho=0.9,wtAR=1,sig=90,tbw=2,padfac=5,ftest=F,fmax=0.1,
speed=0.5,pl=2,graphfile=0)
```

### Arguments

`etpdat` |
Eccentricity, tilt, precession astronmical series. First column = time, second column = ETP. If not entered will use default series from Laskar et al. (2004), spanning 0-1000 kyr. |

`nsim` |
Number of simulations. |

`rho` |
AR(1) coefficient for noise modeling. |

`wtAR` |
Multiplicative factor for AR1 noise (1= eqivalent to ETP variance). If < 0, etp signal will be excluded from the simulations (noise only) |

`sig` |
Demarcate what confidence level (percent) on plots? |

`tbw` |
MTM time-bandwidth product. |

`padfac` |
Pad with zeros to (padfac*npts) points, where npts is the number of data points. |

`ftest` |
Include MTM harmonic f-test results? (T or F) |

`fmax` |
Maximum frequency for plotting. |

`speed` |
Set the amount of time to pause before plotting new graph, in seconds. |

`pl` |
Plot (1) log frequency-log power or (2) linear frequency-linear power? |

`graphfile` |
Output a pdf or jpg image of each plot? 0 = no, 1 = pdf, 2 = jpeg. If yes, there will be no output to screen. Individual graphic files will be produced for each simluation, for assembling into a movie. |

### Details

Note: Setting wtAR=1 will provide equal variance contributions from the etp model and the ar1 model. More generally, set wtAR to the square root of the desired variance contribution (wtAR=0.5 will generate an AR1 model with variance that is 25% of the etp model). If you would like to exclusively evaluate the noise (no etp), set wtAR < 0.

Note: You may use the function etp to generate eccentricity-tilt-precession models.

### 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.

### See Also

### Examples

```
## Not run:
# run simulations using the default settings
ar1etp()
# compare with a second model:
# generate etp model spanning 0-2000 ka, with sampling interval of 5 ka.
ex1=etp(tmin=0,tmax=2000,dt=5)
# run simulations, with rho=-.7, and scaling noise to have 50
ar1etp(etpdat=ex1,rho=0.7,wtAR=sqrt(0.5))
## End(Not run)
```

*astrochron*version 1.3 Index]