ET.Hamon {Evapotranspiration}

Hamon Formulation

Description

Implementing the Hamon formulation for estimating potential evapotranspiration.

Usage

## S3 method for class 'Hamon'
ET(data, constants = NULL, ts="daily", message="yes", AdditionalStats="yes",
save.csv="no", ...)

Arguments

data

A list of data which contains the following items (climate variables) required by Hamon formulation:
Tmax, Tmin (degree Celcius), n (hour)

constants

Dummy argument with a NULL value.

ts

Must be either daily, monthly or annual, which indicates the disired time step that the output ET estimates should be on. Default is daily.

message

Must be either yes or no, indicating whether message should be printed for calculation summary including the following elements:
- ET model name and ET quantity estimated
- Time step of the output ET estimates (i.e. the value of argument ts)
- Units of the output ET estimates
- Time duration of the ET estimation
- Number of ET estimates obtained in the entire time-series
- Basic statistics of the estimated ET time-series including mean, max and min values.

AdditionalStats

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

save.csv

Must be either yes or no, indicating whether a .csv of ET estimates should be saved to working directory.

...

Dummy for generic function, no need to define.

Details

This formulation provides a single calculation method with no alternatives available.

Value

The function generates a list containing the following components:

ET.Daily

Daily aggregated estimations of Hamon potential evapotranspiration.

ET.Monthly

Monthly aggregated estimations of Hamon potential evapotranspiration.

ET.Annual

Annually aggregated estimations of Hamon potential evapotranspiration.

ET.MonthlyAve

Monthly averaged estimations of daily Hamon potential evapotranspiration.

ET.AnnualAve

Annually averaged estimations of daily Hamon potential evapotranspiration.

ET_formulation

Name of the formulation used which equals to Hamon.

ET_type

Type of the estimation obtained which is Potential Evapotranspiration.

Author(s)

Danlu Guo

References

Hamon, W. R. 1961. Estimating potential evapotranspiration. Journal of the Hydraulics Division, 87, 107-120.

Oudin, L., Hervieu, F., Michel, C., Perrin, C., Andreassian, V., Anctil, F.Loumagne, C. 2005, Which potential evapotranspiration input for a lumped rainfall-runoff model?: Part 2-Towards a simple and efficient potential evapotranspiration model for rainfall-runoff modelling. Journal of Hydrology, vol. 303, no. 1-4, pp. 290-306.

See Also

ET,processeddata

Examples

# Use processed existing data set and constants from kent Town, Adelaide
data("processeddata")
data("constants")

# Call ET.Hamon under the generic function ET
results <- ET.Hamon(processeddata, ts="daily", message="yes", AdditionalStats="yes", save.csv="no")