Evapotranspiration (version 1.7)

ET.Hamon: Hamon Formulation

Description

Implementing the Hamon formulation for estimating potential evapotranspiration.

Usage

## S3 method for class 'Hamon':
ET(data, constants, \dots)

Arguments

data

A list of data in class "Hamon" which contains the following items (climate variables) required by Hamon formulation: "Tmax", "Tmin", "n" or "Cd"

constants

A list named "constants" consists of constants required for the calculation of Hamon formulation which must contain the following items: "Elev" - ground elevation above mean sea level in m, "lambda" - latent heat of vaporisation = 2.45 MJ.kg^-1,

...

Dummy for generic function, no need to define.

Value

• This function returns a object of class Hamon. Such objects are list with components:
• ET.Daily
  A zoo object containing daily aggregated estimations of Hamon potential evapotranspiration.
• ET.Monthly
  A zoo object containing monthly aggregated estimations of Hamon potential evapotranspiration.
• ET.Annual
  A zoo object containing annually aggregated estimations of Hamon potential evapotranspiration.
• ET.MonthlyAve
  A zoo object containing monthly averaged estimations of daily Hamon potential evapotranspiration.
• ET.AnnualAve
  A zoo object containing annually averaged estimations of daily Hamon potential evapotranspiration.
• ET_formulation
  A character string containing the name of the formulation used which equals to "Hamon".
• ET_type
  A character string containing the 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.

Examples

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

# Set data class to be "Hamon" to call function
funname <- "Hamon" 
class(data) <- funname 

# Call generic function ET(data, ...) with class "Hamon"
results <- ET(data, constants)