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net.simplace.usermodules.ET_Study.CropEvapoTranspirationWaterStress

Calculates the water stress coefficient K_s using formulas from (FAO 56).

Implemented methods: Allen et al (1998), equations 82, 83 and 84.

K_s reduces PotentialTranCrop and ETC, giving the outputs ActualTranCrop and ETC_adj.

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	cNominalDepletionFactor	Nominal depletion factor	DOUBLE	m	0.0	1.0	-
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	iActualSoilEvapCrop	Actual rate of evaporation from the soil	DOUBLE	mm/d	0.0	20.0	-
input	iMD95	Number of soil layers containing roots (provided by other SimComponents e.g. SlimRoots)	INT	1	0	1000	-
input	iPotentialTranCrop	Potential rate of transpiration from the crop	DOUBLE	mm/d	0.0	20.0	-
input	iTotalWaterContentPerLayer	Total water content in each soil layer (mm)	DOUBLEARRAY	mm	0.0	-	-
ActualTranCrop	Adjusted rate of transpiration from the soil under water stress conditions	DOUBLE	mm/d	null
ETC_adj	Adjusted crop ET under water stress conditions	DOUBLE	mm/d	null
Ks	Water stress coefficient	DOUBLE	1	null

public class CropEvapoTranspirationWaterStress extends
net.simplace.simulation.model.FWSimComponent {
// Public Constructors
public CropEvapoTranspirationWaterStress();

// Public Instance Methods

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

Create the FWSimVariables as interface for this SimComponent

// Protected Instance Methods

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

Initialises the fields by getting input and output FWSimVariables from VarMap

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

Process the algorithm and write the results back to VarMap

protected double TAW(int rootLayerCount);

Total available water in the root zone

rootLayerCount

returns

protected double WR_r(int rootLayerCount);

Retained + mobile water above WP in root zone [mm]

rootLayerCount

returns

protected double p(double ETC);

Adjustment of depletion factor p according to formula in footnote 2 of Table 22 (Allen et al., 1998).

ETC

returns

protected double WaterStressFactor(double ETC, int rootLayerCount);

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

creates a clone from this SimComponent for use in other threads

}

Hierarchy: java.lang.Object - net.simplace.simulation.model.FWSimComponent (net.simplace.simulation.util.FWSimFieldContainer) - CropEvapoTranspirationWaterStress