Simplace Documentation

net.simplace.sim.components.experimental.fao56.CropEvapoTranspirationSoilEvap

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

For full documentation of the formulas please check the original reference (FAO56)

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	iET0	reference crop evapotranspiration	DOUBLE	mm	0.0	20.0	0.0
input	iKcMax	Upper limit on ETC	DOUBLE	1	0.0	2.0	-
input	iKcb	Basal crop coefficient	DOUBLE	1	0.0	2.0	-
input	iKeUpper	Upper limit of soil evaporation coefficient	DOUBLE	1	0.0	2.0	-
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	-	-
out	ActualSoilEvapCrop	Actual rate of evaporation from the soil	DOUBLE	mm/d	0.0	20.0	0.0
out	ETC	Crop ET under standard conditions (no water, nutrient, weed, pest or disease limitations to growth)	DOUBLE	mm/d	0.0	20.0	-
out	Ke	Soil evaporation coefficient	DOUBLE	1	0.0	2.0	-
out	Kr	Soil evaporation reduction coefficient	DOUBLE	1	0.0	1.0	-

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

0.0

1.0

constant

cREW

Readily evaporable water over the full evaporation depth

DOUBLE

0.0

100.0

constant

cSoilLayerDepth

Depth of the bottom of each soil layer after soil layer transformation

DOUBLEARRAY

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

iET0

reference crop evapotranspiration

DOUBLE

0.0

20.0

0.0

input

iKcMax

Upper limit on ETC

DOUBLE

0.0

2.0

input

iKcb

Basal crop coefficient

DOUBLE

0.0

2.0

input

iKeUpper

Upper limit of soil evaporation coefficient

DOUBLE

0.0

2.0

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

0.0

out

ActualSoilEvapCrop

Actual rate of evaporation from the soil

DOUBLE

mm/d

0.0

20.0

0.0

out

ETC

Crop ET under standard conditions (no water, nutrient, weed, pest or disease limitations to growth)

DOUBLE

mm/d

0.0

20.0

out

Soil evaporation coefficient

DOUBLE

0.0

2.0

out

Soil evaporation reduction coefficient

DOUBLE

0.0

1.0

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

Create the FWSimVariables as interface for this SimComponent

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 therefore 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