Evapotranspiration (version 1.9)

ET.Hamon: Hamon Formulation

Description

Implementing the Hamon formulation for estimating potential evapotranspiration.

Usage

## S3 method for class 'Hamon':
ET(data, constants = NULL, ts="daily", \dots)

Arguments

data

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

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.

...

Dummy for generic function, no need to define.

Value

• The function prints a calculation summary to the screen containing 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. The function also generates a list containing the following components, which is saved into a csv file named as ET_Hamon.csv in the working directory:
• 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.

Details

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

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,data

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(data, ts="daily")