Evapotranspiration (version 1.7)

ET.JensenHaise: Jensen-Haise Formulation

Description

Implementing the Jensen-Haise formulation for estimating potential evapotranspiration.

Usage

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

Arguments

data

A list of data in class "JensenHaise" which contains the following items (climate variables) required by Jensen-Haise formulation: "Tmax", "Tmin"

constants

A list named "constants" consists of constants required for the calculation of Penman 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,

solar

Must be either "data", "sunshine hours", "cloud" or "monthly precipitation". "data" indicates that solar radiation data is to be used directly for calculating evapotranspiration; "sunshine hours" indicates that solar radiation is to be calculated using th

...

Dummy for generic function, no need to define.

Value

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

JENSEN, M. E. & HAISE, H. R. 1963. Estimating evapotranspiration from solar radiation. Proceedings of the American Society of Civil Engineers, Journal of the Irrigation and Drainage Division, 89, 15-41.

Examples

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

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

# Call generic function ET(data, ...) with class "JensenHaise"
results <- ET(data, constants, solar = "sunshine hours")