Package net.simplace.sim.components.evapotran.fao56

Class ReferenceETHargreaves

java.lang.Object

net.simplace.sim.model.FWSimComponent

net.simplace.sim.components.evapotran.fao56.ReferenceETHargreaves

All Implemented Interfaces:

net.simplace.sim.util.FWSimFieldContainer

public class ReferenceETHargreaves
extends net.simplace.sim.model.FWSimComponent

Calculates reference evapotranspiration ET0 by Hargreaves method using solar radiation and temperature

Hargreaves 1975

Uses the Hargreaves 1975 formula for ET0 calculation from temperature and solar radiation

\( ET0 = 0.0135 (MeanTemperature + 17.8) SolarRadiationMM \)

Where

\( SolarRadiationMM = 0.408 \cdot \text{iSolarRadiation} \)

is the solar radiation in mm/day, converted from MJ/(m^2 d). For conversion the user can use the fixed factor 0.408 or - by setting cConvertLeByTemp to true - the latent heat of vaporisation as a function of daily mean temperature 1/(2.501-0.002361*Tmean).

Notice: Hargreaves & Sarmani 1985

The Hargreaves & Sarmani 1985 formula is

\( ET0 = 0.0023(MeanTemperature + 17.8) \sqrt{MaxTemp - MinTemp} \cdot ExtraterrestrialRadiationMM \)

To use Hargreaves & Sarmani method, link the output SolarRadiation from the SimComponent SolarRadiationFromTemperature to the input iSolarRadiation of ReferenceETHargreaves.

References

• Hargreaves G. H. 1975. Moisture availability and crop production. Transactions of the American Society of Agricultural Engineers 18:980-984.
• Hargreaves G. H. and Z. A. Samani, 1985. Reference crop evapotranspiration from temperature. Appl. Eng. Agric. 1, 96-99.

Author:

Gunther Krauss, gk@uni-bonn.de

Component Variables

Content Type	Name	Description	Data Type	Unit	Min Value	Max Value	Default Value
constant	cConvertLeByTemp	Use latent heat (Le) of vaporisation as a function of temperature to convert radiation from MJ/(m^2 day) to mm/day.	BOOLEAN		-	-	false
input	iSolarRadiation	solar radiation	DOUBLE	MJ/(m2 d)	-	-	0.0
input	iTMax	maximum daily temperature	DOUBLE	°C	-	-	0.0
input	iTMin	minimum daily temperature	DOUBLE	°C	-	-	0.0
out	ReferenceCropEvapotranspiration	reference evapotranspiration (ET0)	DOUBLE	mm/d	-	-	0.0

Nested Class Summary

Nested classes/interfaces inherited from class net.simplace.sim.model.FWSimComponent

net.simplace.sim.model.FWSimComponent.TEST_STATE

Field Summary

Fields inherited from class net.simplace.sim.model.FWSimComponent

iFieldMap, iFrequence, iInputMap, iJexlRule, iMasterComponentGroup, iName, iOrderNumber, isComponentGroup, iSimComponentElement, iSimModel, iVarMap

Constructor Summary

Constructors

Constructor	Description
ReferenceETHargreaves()	Empty constructor used by class.forName()

Method Summary

Modifier and Type	Method	Description
protected net.simplace.sim.model.FWSimComponent	clone(net.simplace.sim.util.FWSimVarMap aVarMap)
HashMap<String,net.simplace.sim.util.FWSimVariable<?>>	createVariables()	Create the FWSimVariables as interface for this SimComponent
HashMap<String,net.simplace.sim.util.FWSimVariable<?>>	fillTestVariables(int aParamIndex, net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)	called for single component test to check the components algorithm.
protected void	init()	Initializes the fields by getting input and output FWSimVariables from VarMap
protected void	process()	Process the algorithm and write the results back to VarMap

Methods inherited from class net.simplace.sim.model.FWSimComponent

addVariable, bind, checkCondition, createSimComponent, createSimComponent, createSimComponent, createSimComponent, doProcess, getConstantVariables, getContentType, getCreateFormXML, getDescription, getEditFormXML, getFieldMap, getFrequence, getFrequenceRuleScript, getInputs, getInputVariables, getMasterComponentGroup, getName, getOrderNumber, getOutputVariables, getVariable, getVariableField, getVarMap, initialize, isConditionCheck, isVariableAvailable, performLinks, performLinks, readInputs, removeVariable, reset, runComponentTest, setVariablesDefault, toComponentLinkingXML, toDocXML, toGroupXML, toOutputDefinitionXML, toResourcesDataXML, toResourcesDefinitionXML, toString, toXML, writeVarInfos

Methods inherited from class java.lang.Object

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

Constructor Details

ReferenceETHargreaves

public ReferenceETHargreaves()

Empty constructor used by class.forName()

Method Details

createVariables

public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> createVariables()

Create the FWSimVariables as interface for this SimComponent

Specified by:

createVariables in interface net.simplace.sim.util.FWSimFieldContainer

Specified by:

createVariables in class net.simplace.sim.model.FWSimComponent

See Also:

• FWSimComponent.createVariables()

init

protected void init()

Initializes the fields by getting input and output FWSimVariables from VarMap

Specified by:

init in class net.simplace.sim.model.FWSimComponent

See Also:

• FWSimComponent.init()

process

protected void process()

Process the algorithm and write the results back to VarMap

Specified by:

process in class net.simplace.sim.model.FWSimComponent

See Also:

• FWSimComponent.process()

fillTestVariables

public HashMap<String,net.simplace.sim.util.FWSimVariable<?>> fillTestVariables(int aParamIndex,
 net.simplace.sim.model.FWSimComponent.TEST_STATE aDefineOrCheck)

called for single component test to check the components algorithm.

Specified by:

fillTestVariables in class net.simplace.sim.model.FWSimComponent

See Also:

• net.simplace.sim.util.FWSimFieldContainer#fillTestVariables(int aParamIndex, TEST_STATE aDefineOrCheck)

clone

protected net.simplace.sim.model.FWSimComponent clone(net.simplace.sim.util.FWSimVarMap aVarMap)

Specified by:

clone in class net.simplace.sim.model.FWSimComponent

See Also:

• FWSimComponent.clone(net.simplace.sim.util.FWSimVarMap)