ET.ChapmanAustralian {Evapotranspiration} | R Documentation |

Implementing the Chapman formulation for estimating potential evapotranspiration.

## S3 method for class 'ChapmanAustralian' ET(data, constants, ts="daily", PenPan= T, solar="sunshine hours", alpha=0.23, message="yes", AdditionalStats="yes", save.csv="no", ...)

`data` |
A list of data which contains the following items (climate variables) required by Chapman formulation: |

`constants` |
A list named The following constants are also required when argument |

`ts` |
Must be either |

`PenPan` |
Must be |

`solar` |
Must be either |

`alpha` |
Any numeric value between 0 and 1 (dimensionless), albedo of the evaporative surface incident radiation that is reflected back at the surface. |

`message` |
Must be either |

`AdditionalStats` |
"yes" or "no" indicating whether monthly averaged and annual averaged ET should be calculated. |

`save.csv` |
Must be either |

`...` |
Dummy for generic function, no need to define. |

The alternative calculation options can be selected through arguments `PenPan`

and `solar`

, please see `Arguments`

for details.

The function generates a list containing the following components:

`ET.Daily` |
Daily aggregated estimations of Chapman potential evapotranspiration. |

`ET.Monthly` |
Monthly aggregated estimations of Chapman potential evapotranspiration. |

`ET.Annual` |
Annually aggregated estimations of Chapman equivalent Penmen-Monteith evapotranspiration. |

`ET.MonthlyAve` |
Monthly averaged estimations of daily Chapman potential evapotranspiration. |

`ET.AnnualAve` |
Annually averaged estimations of daily Chapman potential evapotranspiration. |

`ET_formulation` |
Name of the formulation used which equals to |

`ET_type` |
Type of the estimation obtained which is |

`message1` |
A message to inform the users about how solar radiation has been calculated by using which data. |

`message5` |
A message to inform the users about if the Class-A pan evaporation is from actual data or from PenPan estimation. |

Danlu Guo

McMahon, T., Peel, M., Lowe, L., Srikanthan, R. & McVicar, T. 2012. *Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis*. Hydrology and Earth System Sciences Discussions, 9, 11829-11910.

Chapman, T. 2001, *Estimation of evaporation in rainfall-runoff models*, in F. Ghassemi, D. Post, M. SivapalanR. Vertessy (eds), MODSIM2001: Integrating models for Natural Resources Management across Disciplines, Issues and Scales, MSSANZ, vol. 1, pp. 293-298.

`ET`

,`processeddata`

,`defaultconstants`

,`constants`

,`ET.PenPan`

# Use processed existing data set and constants from kent Town, Adelaide data("processeddata") data("constants") # Call ET.ChapmanAustralian under the generic function ET results <- ET.ChapmanAustralian(processeddata, constants, ts="daily", PenPan= TRUE, solar="sunshine hours", alpha=0.23, message="yes", AdditionalStats="yes", save.csv="no")

[Package *Evapotranspiration* version 1.15 Index]