This function uses weighted survival regression to estimate three surfaces that cover the complete range of DecYear and log(Q) values in the Daily data set. These surfaces are: (1) is the estimated log concentration (yHat), (2) is the estimated standard error (SE), (3) is the estimated concentration (ConcHat). They are mapped as an array that covers the complete space of daily discharge and time. The first index is discharge, layed out in 14 equally spaced levels of log(Q). The second index is time, layed out as 16 increments of the calendar year, starting January 1. It returns the 3 dimensional array called surfaces. This array will be used to estimate these 3 quantities for any given day in the daily values record.

1 2 | ```
estSurfaces(eList, windowY = 7, windowQ = 2, windowS = 0.5,
minNumObs = 100, minNumUncen = 50, edgeAdjust = TRUE)
``` |

`eList` |
named list with at least the Sample and Daily dataframes |

`windowY` |
numeric specifying the half-window width in the time dimension, in units of years, default is 7 |

`windowQ` |
numeric specifying the half-window width in the discharge dimension, units are natural log units, default is 2 |

`windowS` |
numeric specifying the half-window with in the seasonal dimension, in units of years, default is 0.5 |

`minNumObs` |
numeric specifying the miniumum number of observations required to run the weighted regression, default is 100 |

`minNumUncen` |
numeric specifying the minimum number of uncensored observations to run the weighted regression, default is 50 |

`edgeAdjust` |
logical specifying whether to use the modified method for calculating the windows at the edge of the record. Default is TRUE. |

surfaces array containing the three surfaces estimated, array is 3 dimensional

1 2 | ```
eList <- Choptank_eList
## Not run: surfaces <- estSurfaces(eList)
``` |

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