SolarandInfraredRadiationMeasurementsFrankVignola,JosephMichalsky,andTomStoffelFeatures

Describesthestrengthsandweaknessesofirradianceinstruments Providesdetailedinformationonhowtoassessuncertaintyinmeasurements Containsinformationonhowtoinstall,operate,andmaintainaradiationmeasurementstation Offerscomprehensivebackgroundinformationneededtounderstandtheuseofsolar

instrumentation Makesrecommendationsonchoosingpyranometersforphotovoltaicmonitoringstations Includeschapter‐endsummaries,questions,references,andusefullinks

SummaryTheratherspecializedfieldofsolarandinfraredradiationmeasurementhasbecomemoreandmoreimportantinthefaceofgrowingdemandsbytherenewableenergyandclimatechangeresearchcommunitiesfordatathataremoreaccurateandhaveincreasedtemporalandspatialresolution.Updatingdecadesofacquiredknowledgeinthefield,SolarandInfraredRadiationMeasurementsdetailsthestrengthsandweaknessesofinstrumentsusedtoconductsuchsolarandinfraredradiationmeasurements.Topicscoveredinclude:

Radiometerdesignandperformance Equipmentcalibration,installation,operation,andmaintenance Dataqualityassessment Methodstousemeasureddatatoestimateirradianceforanysurface

Withabroadrangeofcontentthatwillbenefitstudentsandmoreexperiencedreadersalike,thisresourceservesasaprimerandtechnicalreferencethatpresentsthebasicterminologyandfundamentalsforresourceassessment.Itexploresthehistoryofsolarradiationinstrumentsandaddressesdirectnormal,global,diffuse,andtiltedmeasurements,aswellasthecharacteristicsofinstrumentsusedforthesemeasurements.Theauthorsconsidermethodsofassessingtheuncertaintyofsolarmeasurementsandthencoveralbedo,infrared,net,andspectralirradiancemeasurementsandinstrumentation.Thebookdevotesasectiontoothermeteorologicalinstruments,andanothertothebasicsforinstallingandoperatingasolarmonitoringstation.Appendicesincludeinformationonsolarresourceassessmentmodelingandsatellite‐derivedirradiance,alongwithotherusefulmaterial.Thisbook’sauthorsareexpertswhoeachhavemorethan30yearsofexperiencedevelopingandoperatingmultiplemeasurementstations,workingwithindustrytoimproveradiometry,andconductingvariousresearchprojects.

ContentsAcknowledgments...................................................................................................xiiiAuthorBiographies.................................................................................................xvPreface..........................................................................................................................xvii

Chapter1MeasuringSolarandInfraredRadiation.................................................1Questions....................................................................................................................5Reference....................................................................................................................5

Chapter2SolarResourceDefinitionsandTerminology.......................................72.1Introduction.......................................................................................................72.2TheSun................................................................................................................72.3ExtraterrestrialRadiation...........................................................................82.4SolarCoordinates............................................................................................9

2.5Zenith,Azimuth,andHourAngles...........................................................142.6Solar,Universal,andLocalStandardTime..........................................162.7SolarPositionCalculation............................................................................172.8SunriseandSunsetTimes............................................................................202.9Global,DirectNormal,andDiffuseIrradiance…………......................222.10SolarRadiationonTiltedSurfaces…………..........................................252.11SpectralNatureofSolarRadiation.........................................................252.12FundamentalsofThermodynamicsandHeatTransfer…............282.12.1Conduction....................................................................................................292.12.2Convection.....................................................................................................302.12.3RadiativeHeatTransfer...........................................................................302.13PhotodiodesandSolarCellPrerequisites............................................312.14Models.................................................................................................................32Questions......................................................................................................................33References...................................................................................................................33

Chapter3HistoricMilestonesinSolarandInfraredRadiationMeasurement..........................................................................35

3.1Introduction........................................................................................................353.2EarliestObservationsoftheSunandtheNatureofLight..............353.3Nineteenth‐CenturyRadiometers.............................................................363.3.1Pouillet’sPyrheliometer(1837).............................................................363.3.2Campbell–StokesSunshineRecorder(1853,1879)......................393.3.3ÅngströmElectricalCompensationPyrheliometer(1893).......413.3.4CallendarPyranometer(1898)...............................................................433.3.5ÅngströmTulipanPyrgeometer(1899)..............................................443.4OperationalRadiometersoftheTwentiethCentury.........................443.4.1AbbotSilver‐DiskPyrheliometer(1906)............................................443.4.2SmithsonianWater‐FlowPyrheliometer(1910)............................463.4.3MarvinPyrheliometer(1910)..................................................................473.4.4ÅngströmPyranometer(1919)...............................................................473.4.5Kipp&ZonenSolarimeter(1924)..........................................................473.4.6RobitzschBimetallicActinograph(1932)...........................................493.4.7Eppley180ºPyrheliometer(1930).......................................................503.4.8EppleyModelPSP(1957)...........................................................................523.4.9YanishevskyPyranometer(1957)..........................................................533.4.10EppleyModelNIP(1957).........................................................................563.4.11EppleyModelPIR(1968)..........................................................................583.4.12PrimaryAbsoluteCavityRadiometer(PACRAD)(1969)...........593.4.13EppleyModel8‐48(1969).......................................................................613.4.14LI‐CORModelLI‐200SA(1971).............................................................623.4.15RotatingShadowbandRadiometer(1975)......................................633.4.16WorldStandardGroup(1979)...............................................................673.5RecentAdvancesinSolarMeasurements................................................673.5.1AutomaticHickey‐FriedenCavityRadiometer..................................673.5.2TotalIrradianceMonitor(TIM)................................................................693.5.3PMODModel8(PMO8)................................................................................71Summary........................................................................................................................71Questions.......................................................................................................................72References.....................................................................................................................72

Chapter4DirectNormalIrradiance..................................................................................774.1OverviewofDirectNormalIrradiance......................................................774.2PyrheliometerGeometry.................................................................................804.3OperationalThermopilePyrheliometers.................................................824.4AbsoluteCavityRadiometers........................................................................864.5UncertaintyAnalysisforPyrheliometerCalibration..........................88

4.6UncertaintyAnalysisforOperationalThermopilePyrheliometers…………………….904.6.1WindowTransmittance,ReceiverAbsorptivity,andTemperatureSensitivity...914.6.2SolarZenithAngleDependence.................................................................................................924.7UncertaintyAnalysisforRotatingShadowbandRadiometerMeasurementsof

DirectNormalIrradiance.........934.8DirectNormalIrradianceModels..................................................................................................954.8.1Ground‐BasedModeling................................................................................................................954.8.2SatelliteModelEstimates..............................................................................................................954.9HistoricalandCurrentSurface‐MeasuredDirectNormalIrradianceData................97Questions.......................................................................................................................................................100References.....................................................................................................................................................100

Chapter5MeasuringGlobalIrradiance...........................................................................................................1035.1IntroductiontoGlobalHorizontalIrradianceMeasurements........................................1035.2Black‐DiskThermopilePyranometers......................................................................................1085.2.1ThermalOffsets................................................................................................................................1135.2.2Nonlinearity......................................................................................................................................1155.2.3SpectralResponse..........................................................................................................................1165.2.4AngleofIncidenceResponse.....................................................................................................1175.2.5ResponseDegradation.................................................................................................................1195.2.6TemperatureDependence..........................................................................................................1205.2.7IceandSnowonDome—Ventilators.....................................................................................1215.2.8AnOpticalAnomaly.......................................................................................................................1225.3Black‐and‐WhitePyranometers..................................................................................................1245.3.1CharacteristicsofBlack‐and‐WhitePyranometers.........................................................1245.3.2LackofThermalOffset.................................................................................................................1285.4Photodiode‐BasedPyranometers...............................................................................................1285.4.1CharacterizingaPhotodiodePyranometer.........................................................................1315.4.2CorrectionsMadetoPhotodiodePyranometers..............................................................1355.4.3ReferenceSolarCells....................................................................................................................1425.5CalibrationofPyranometers.........................................................................................................1435.5.1Shade–UnshadeCalibrationMethod.....................................................................................1445.5.2SummationMethodCalibration..............................................................................................1465.6PyranometerCalibrationUncertainties...................................................................................1495.6.1UncertaintyAnalysisAppliedtoPyranometerCalibration.........................................1505.6.2AnExampleoftheGUMProcedureAppliedtotheCalibrationUncertainties

ofaPyranometer...........153Questions......................................................................................................................................................156References....................................................................................................................................................157UsefulLinks.................................................................................................................................................159

Chapter6DiffuseIrradiance................................................................................................................................1616.1Introduction.........................................................................................................................................1616.2TheMeasurementofDiffuseIrradiance..................................................................................1626.2.1FixedShadowbandMeasurementsofDiffuseIrradiance.............................................1636.2.2CalculatedDiffuseIrradianceversusShadeDiskDiffuse.............................................1656.2.3RotatingShadowbandDiffuseMeasurements..................................................................1666.3CalibrationofDiffusePyranometers.........................................................................................1676.4ValueofAccurateDiffuseMeasurements................................................................................168Questions......................................................................................................................................................169References....................................................................................................................................................170

Chapter7RotatingShadowbandRadiometers............................................................................................1717.1Introduction.........................................................................................................................................1717.2TheRotatingShadowbandRadiometer...................................................................................1737.3TheMultifilterRotatingShadowbandRadiometer.............................................................178Questions......................................................................................................................................................181References....................................................................................................................................................182

Chapter8MeasuringSolarRadiationonaTiltedSurface........................................................................1838.1Introduction..........................................................................................................................................1838.2EffectofTiltonSingleBlackDetectorPyranometers.........................................................1848.3EffectofTiltonBlack‐and‐WhitePyranometers..................................................................1858.4EffectofTiltonPhotodiodePyranometers.............................................................................1878.5RecommendationsforTiltedIrradianceMeasurements...................................................1888.6NotesonModelingPVSystemPerformancewithPhotodiodePyranometers........189Questions........................................................................................................................................................191References......................................................................................................................................................191

Chapter9Albedo.........................................................................................................................................................1939.1Introduction...........................................................................................................................................1939.2BroadbandAlbedo..............................................................................................................................1939.3SpectralAlbedo....................................................................................................................................1949.4BidirectionalReflectanceDistributionFunction..................................................................2009.5AlbedoMeasurements......................................................................................................................2019.5.1Broadbandalbedo..........................................................................................................................2019.5.2Spectralalbedo................................................................................................................................203Questions......................................................................................................................................................203References....................................................................................................................................................204

Chapter10InfraredMeasurements..................................................................................................................20510.1Introduction.......................................................................................................................................20510.2Pyrgeometers....................................................................................................................................20610.3Calibration..........................................................................................................................................20910.4ImprovedCalibrations..................................................................................................................21010.5OtherPyrgeometerManufacturers.........................................................................................21210.6OperationalConsiderations........................................................................................................213Questions......................................................................................................................................................215References....................................................................................................................................................215

Chapter11NetRadiationMeasurements......................................................................................................21711.1Introduction......................................................................................................................................21711.2Single‐Sensor(All‐Wave)NetRadiometers........................................................................21811.3Two‐SensorNetRadiometers...................................................................................................22011.4Four‐SensorNetRadiometers..................................................................................................22211.5AccuracyofNetRadiometers....................................................................................................22311.6ABetterNetRadiationStandard.............................................................................................22311.7NetRadiometerSources.............................................................................................................224Questions.....................................................................................................................................................224References...................................................................................................................................................224

Chapter12SolarSpectralMeasurements.....................................................................................................22712.1Introduction.....................................................................................................................................22712.2TheExtraterrestrialSolarSpectrum.....................................................................................22712.3AtmosphericInteractions..........................................................................................................22812.3.1RayleighScattering...................................................................................................................22912.3.2AerosolScatteringandAbsorption...................................................................................22912.3.3GasAbsorption...........................................................................................................................23112.3.4TransmissionoftheAtmosphere.......................................................................................23612.4BroadbandFilterRadiometry.................................................................................................23712.4.1Photometry..................................................................................................................................23712.4.2PhotosyntheticallyActiveRadiation(PAR)...................................................................24012.4.3UVAandUVB...............................................................................................................................24112.5Narrow‐BandFilterRadiometry............................................................................................24212.5.1AerosolOpticalDepth.............................................................................................................24212.5.2WaterVapor................................................................................................................................24512.5.3SunRadiometers.......................................................................................................................24712.6Spectrometry.................................................................................................................................248

12.6.1Spectrometers.............................................................................................................................24912.6.2SpectralModels..........................................................................................................................249Questions....................................................................................................................................................250References..................................................................................................................................................250

Chapter13MeteorologicalMeasurements..................................................................................................25513.1Introduction.....................................................................................................................................25513.2AmbientTemperature.................................................................................................................25513.2.1TypesofTemperatureSensors............................................................................................25613.2.2ResponseTimes..........................................................................................................................25613.2.3MeasuringTemperature.........................................................................................................25613.3WindSpeedandWindDirection.............................................................................................25813.3.1SensorTerminology..................................................................................................................25813.3.2Anemometer.................................................................................................................................26013.3.3CupAnemometers......................................................................................................................26013.3.4PropellerAnemometers...........................................................................................................26113.3.5SonicAnemometers...................................................................................................................26313.3.6InstallingAnemometers...........................................................................................................26313.3.7WindVanes....................................................................................................................................26413.4RelativeHumidity...........................................................................................................................26513.5Pressure..............................................................................................................................................26713.5.1AneroidDisplacementTransducers...................................................................................26813.5.2PiezoresistiveBarometers......................................................................................................26813.5.3PiezocapacitanceBarometers...............................................................................................26913.6RecommendedMinimumAccuraciesforOperationalInstruments.........................270Questions......................................................................................................................................................270References....................................................................................................................................................271

Chapter14SettingUpaSolarMonitoringStation......................................................................................27314.1Introduction......................................................................................................................................27314.2ChoosingaSite.................................................................................................................................27414.3GroundingandShielding.............................................................................................................27614.4DataLoggerandCommunications..........................................................................................27614.5MeasurementInterval..................................................................................................................27814.6CleaningandMaintenance..........................................................................................................27914.7RecordKeeping................................................................................................................................28314.8ImportanceofReviewingData..................................................................................................28314.9QualityControlofData.................................................................................................................28714.10FieldCalibrations.........................................................................................................................29014.11PhysicalLayoutofaSolar‐MonitoringStation................................................................291Questions......................................................................................................................................................294References....................................................................................................................................................294

AppendixA:ModelingSolarRadiation........................................................................................................295AppendixB:SolarRadiationEstimatesDerivedfromSatelliteMeasurements................311AppendixC:SunPathCharts..............................................................................................................................321AppendixD:SolarPositionAlgorithms.......................................................................................................341AppendixE:UsefulConversionFactors.......................................................................................................349AppendixF:SourcesforEquipment..............................................................................................................353AppendixG:BORCALReport..............................................................................................................................359AppendixH:SunshineDuration.......................................................................................................................375AppendixI:FailureModes...................................................................................................................................377