Package net.simplace.usermodules.roelof

Class EquationsFAO56

java.lang.Object
net.simplace.usermodules.roelof.EquationsFAO56
public class EquationsFAO56 extends Object
Helper EquationsFAO56 for computing values due to equations from (FAO 56) WIKI_START Equation numbers refers to the paper cited below. == References == [http://www.fao.org/docrep/x0490e/x0490e00.htm (FAO 56): Allen, Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56, 1998] WIKI_END
Author:
Roelof Oomen

  • Constructor Summary

    Constructors
    Constructor
    Description
    EquationsFAO56()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected double
    K_r(double D_e, double TEW, double REW)
    Calculates evaporation reduction factor K_r according to FAO56, Ch. 7.
    protected double
    K_s(double p, double D_r, double TAW)
    Calculate water stress factor K_s according to FAO56, Ch. 8 (Eq. 83 & 84.).

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • EquationsFAO56

      public EquationsFAO56()

  • Method Details

    • K_s

      protected double K_s(double p, double D_r, double TAW)
      Calculate water stress factor K_s according to FAO56, Ch. 8 (Eq. 83 & 84.).
      Parameters:
      p - Depletion factor
      D_r - Root zone depletion (FC - retained above WP) [mm]
      TAW - Total available water in the root zone [mm]

    • K_r

      protected double K_r(double D_e, double TEW, double REW)
      Calculates evaporation reduction factor K_r according to FAO56, Ch. 7. Note: Allen et al (1998) explicitly specifies K_r = 1 when soil surface is wet, which is also the case here, as when WM > 0, WR = FC, and therefore D_e will be zero.
      Parameters:
      D_e - Evaporation zone depletion (FC - retained above 0.5*WP) [mm]
      TEW - Total evaporable water (i.e., maximum depth of water that can be evaporated from the soil surface layer) [mm]
      REW - Readily evaporable water: depletion at which evaporation starts to become limited [mm]