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net.simplace.usermodules.ET_Study.SoilEvaporationReduction

Calculates the soil evaporation reduction coefficient K_r using formulas from (FAO 56).

Implemented methods: Allen et al (1998), equations 73 and 74.

For full documentation of the formulas please check the original reference (FAO 56)

References: Allen et al., 1998. Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56, 1998 http://www.fao.org/docrep/x0490e/x0490e00.htm

Component Variables

Content Type	Name	Description	Data Type	Unit	Min Value	Max Value	Default Value
constant	cMaxSoilEvaporationDepth	Depth of the surface soil layer that is subject to drying by way of evaporation (Z_e)	DOUBLE	m	0.0	1.0	-
constant	cREW	Readily evaporable water over the full evaporation depth	DOUBLE	mm	0.0	100.0	-
constant	cSoilLayerDepth	Depth of the bottom of each soil layer after soil layer transformation	DOUBLEARRAY	m	-	-	-
constant	cSoilWaterFieldCapacity	Volumetric soil water content of each layer at field capacity (pF2.5 or -33 KPa)	DOUBLEARRAY	m3/m3	-	-	-
constant	cSoilWaterWiltingPoint	Volumetric soil water content of each layer at permanent wilting point (pF4.2 or -1500 KPa)	DOUBLEARRAY	m3/m3	-	-	-
input	iTotalWaterContentPerLayer	Total water content in each soil layer (mm)	DOUBLEARRAY	mm	0.0	-	-
out	K_r	Soil evaporation reduction coefficient	DOUBLE	1	0.0	1.0	-

public class SoilEvaporationReduction extends
net.simplace.sim.model.FWSimComponent {
// Public Constructors
public SoilEvaporationReduction();

// Public Instance Methods

public HashMap createVariables(); // Defines
net.simplace.sim.model.FWSimComponent

Create the FWSimVariables as interface for this SimComponent

// Protected Instance Methods

protected void init(); // Defines net.simplace.sim.model.FWSimComponent

Initialises the fields by getting input and output FWSimVariables from VarMap

protected void process(); // Defines net.simplace.sim.model.FWSimComponent

Process the algorithm and write the results back to VarMap

protected double EvaporationReduction();

Calculates K_r. Allen et al (1998) specifies K_r = 1 when soil surface is wet, which also the case here, as when WM > 0, WR = FC and D_e will be zero.

protected FWSimComponent clone(FWSimVarMap aVarMap);
// Defines net.simplace.sim.model.FWSimComponent

creates a clone from this SimComponent for use in other threads

}

Hierarchy: java.lang.Object - net.simplace.sim.model.FWSimComponent (net.simplace.sim.util.FWSimFieldContainer) - SoilEvaporationReduction