Decagon’s Assets:改善: Kaizenn Continual improvement: in design,manufacturing, and all processes
Decagon’s Thermal and ElectricalConductivity Probe (TECP):2007 Mars Lander
TECP objectivesn Learn more about how heatflows in Martian regolithn Ground-truth for plentiful remotesensing datan Determine if unfrozen watermay exist under sunlitconditions in trenchn Answers: “Can liquid wateroccur on Mars?”n Study vapor phase watertransportn Examine how ice migrates frompole to polePrototype TECP probe
WP4C Dewpoint Water Potential Metern Measures Water Potential of Soils, Seeds,Organic Matter, etc.directly MPa and Pf (logbase 10 of MPa)n Easy to use, more robust than thermocouplepsychrometersn Temp. controlledn Range: -0.05 to -300MPa
Chilled-mirrorDewpoint TechniqueInfrared SensorOptical SensorMirror is chilled until dew isformed. The temperature at whichsaturation is achieved isdetermined by observingcondensation on a chilled surface(mirror).Advantages• Wide measurement range• Rapid measurement ~ 5 min.• High reliability• Low MaintenanceSampleMirrorFan
pF Plot to get Soil Swellingy = -17.02x + 7.0381R2= 0.9889y = -29.803x + 7.0452R2= 0.9874y = -97.468x + 6.8504R2= 0.968833.544.555.566.577.50 0.05 0.1 0.15 0.2Water Content (g/g)Suction(pF)L-soilPalousePalouse B
Expansive Soil Classification fromMcKeen(1992)Class Slope ExpansionI > -6 special caseII -6 to -10 highIII -10 to -13 mediumIV -13 to -20 lowV < -20 non-expansive
Vapor Sorption Analyzer (VSA)20Range: -10 to -475 MPa.Accuracy: ±1MPa or ±1%Operating Temperature: 15 to 40°C• Auto-generated moisture releasecurves• Static humidity feature to watchhow soil adsorbs water over time
AccuPAR Ceptometermodel LP-80What does the AccuPAR Measure?n PAR (Photosynthetically ActiveRadiationn LAI (Leaf Area Index) calculatedusing PAR measurements aboveand below the canopy, and usingother variables.Decagon invented this type ofinstrument in 1988 (Sunread, Sunscan,PAR-80, LP-80)
What is PAR? n Acronym forPhotosyntheticallyActive Radiation.n Defined as the light inthe 400 to 700 nmrange of thespectrum (visiblerange).n Light that is mostuseful to plants forphotosynthesis.n Expressed byAccuPAR asµmol m-2 s-1, ameasure of photonflux densityElectromagnetic Spectrum
Leaf Area Index (LAI)What is LAI?n Defined as: total leaf areaper unit ground arean Indication of Canopy density,biomassn Used to monitor growth,infestationn Often used for ground-truthing Remote Sensing LAIdata
Calculating LAIn Above-canopy PARn Below-canopy PARn x (leaf distribution parameter)n Zenith angle (automatically calculated)n Fb (fraction of beam radiation)AccuPAR calculates LAI based on equationsfrom Goudraan, Norman, and Campbell usingmeasured and supplied data:
Comparison Studies“Comparisons of three Leaf Area Index Meters in aCorn Canopy” by W.W. Wilhelm, K. Ruwe, M.R.Schlemmer in Crop Science 40:1179-1183 (2000)n Shows that all three types are similar, AccuPAR/SunScan somewhat better than LAI-2000.
Spectral Reflectance Sensors (SRS)• NDVI bands: 630 nm and 800 nm center wavelengths • PRI bands: 532 nm and 570 nm center wavelengths • NIST traceable calibra5on stored onboard • Cosine diﬀusers for hemispherical measurement • 20° sealed ﬁeld stops for direc5onal measurements • Dimensions: 43 x 40 x 27 mm • Epoxy-‐sealed sensor body – robust design • SDI-‐12 digital sensor • Decagon Em50 and CSI datalogger compa5ble PRIPRINDVINDVI Hemispherical view sensorsDirectional field stop sensorStacked SRS sensorsNDVI + PRI
How to Measure NDVI and PRIPRINDVINDVINDVIPRIOnly two bands are needed to calculated NDVI or PRI.
Typical canopy reflectance spectrumredNIRredNIRNDVIρρρρ+−=Calculating NDVINIRred• NDVI is calculated frommeasurements of percentreflectance (ρ) in the red andnear-infrared (NIR) regions ofthe electromagnetic spectrum.• Percent reflectance is the ratiobetween upwelling (from thecanopy) to downwelling (fromthe sky) radiation. Requires ameasurement of both.• Red band is related tochlorophyll content (highabsorption), NIR band isrelated to leaf cell structure(high scattering).NDVI values range from -1 to 1.
Gamon & Surfus (1999) New Phyt.570531570531ρρρρ+−=PRICalculating PRI• PRI (PhotochemicalReflectance Index) wasdesigned to estimate LightUse Efficiency (LUE) bydetecting changes in thexanthophyll cycle• Xanthophyll pigmentschange rapidly inresponse to environmentalconditionsPRI values range from -1 to 1.
Measurement ConsiderationsImage credit: Chris Gough• Reflectance measurements require atop-down view of the canopy tomeasure upwelling radiance.• Up-looking sensors requireunobstructed view of the sky.• Dual-view instruments (up/down) area convenient way of measuring bothincident and reflected light forcalculating percent reflectance. Theyalso account for changing skyconditions (e.g., clear vs. cloudy skyconditions).• SRS are lightweight, low power, andhave a small footprint, making themeasy to mount almost anywhere.DownwellingradiationUpwellingradiation
LeafPorometerModel SC-1For measurement ofstomatal conductance• Steady-state technique• Stomatal conductance is aprimary indicator of plant stressunder drought conditions
How does it work?n A chamber with a fixeddiffusion path is clamped tothe leaf surfacen Steady-state technique;measures vapor pressure attwo locations in a fixeddiffusion pathn Calculates flux and gradientfrom the vapor pressuremeasurements and the knownconductance of the diffusionpath.AtmosphereDesiccant
What can I do with a porometer?n Water use and water balancen Use conductance with Fick’s law to determine croptranspiration raten Develop crop cultivars for dry climates/salt affectedsoilsn Determine plant water stress in annual andperennial speciesn Study effects of environmental conditionsn Schedule irrigationn Optimize herbicide uptaken Study uptake of ozone and other pollutants
Case study: Washington StateUniversity wheat• Researchers using steady state porometerto create drought resistant wheat cultivars– Evaluating physiological response to droughtstress (stomatal closing)– Selecting individuals with optimal response
Case Study: Stress in wine grapesy = 0.0204x - 12.962R² = 0.5119-20.0-18.0-16.0-14.0-12.0-10.0-8.0-6.0-4.0-2.00.0050100150200250300350400450500Mid-dayLeafWaterPotential(bars)Stomatal Conductance (mmol m-2 s-1)
Dielectric SoilMoisture Sensorsn Hi-frequency capacitance (FDR)-- Measures the dielectric constantof the soiln Designed to be buried in soil forlong-term monitoring of soil moisturen Measurement is made by processorinside probe head
Analog soil moisture sensors10HS: 10 cm probe length,3-15 VDC— large sample area (~1 liter)EC-5: 5cm probe length,2.5-3 VDC— smallest lengthMAS-1: 4-20 mA sensor,5cm probe length— smallest length
Digital SensorsGS3: Water content, EC(0-23 dS/m) andtemperature. For soil or soil-less substrates5TE: Water content, EC(0-23 dS/m) andtemperature. For field soilsonly.5TM: Water content andtemperature. For field soilsAll digital sensors are SDI-12 compatible
Em50 Data Loggern Weatherproof,-40° to 45°Cmeasurementn 5 portsn Uses 5 AA alkaline batteries,low power usage.n Programmed via RS232 cableconnected to COM Port.n Measures every minute, thenaverages and stores readingsaccording to how it’sprogrammed. It can store anyinterval between 1min. and 1day.n Measures other micro-environment sensors thatDecagon sellsStorage Capacity:1MB non-volatile flash(28,672 scans on all 5ports).
VP3 RH/Temp Sensorand Radiation shieldn Digital sensor for use with Em50loggersn Measures and logs vapor pressureand temperature with a capacitancesensor and thermistorn Should be used with a radiationshield for outdoor use
Temperature Sensorn Measures from – 40°C to60°Cn Accuracy: ±0. 5 ° from 5 to40°C; ±1°C outside thisrangen Can be used in air, soil, orliquid. If used in air, aradiation shield should beused.
Leaf Wetness Sensorn Determines presence andduration of leaf moisturen Similar technology to EC-5,does not require painting ormaintenancen All probes are calibrated tosame dryness baselinevoltagen Water condenses andevaporates from the surfaceat the same rate as it doeson leaves
MPS-2 MatricPotential Sensorn For in-situ monitoringof water potentialn Range: -10 to -500kPa(pF 2 to pF 3.71)n Uses capacitancemethod to measurewater content of aknown ceramic matrix
Sensor Theoryn Measure water content of a known porous material witha pre-established SWCC, giving us matric waterpotential.Matrix (Side View) Sensor (Side View)ConfinedEM FieldMetal PlateMetal Plate
MPS-2 Advantagesn No maintenancen Good accuracy in plant-availablerangen Each sensor pre-calibratedn Also measures Soil temperatureWater Potential is a betterindicator of plant available waterthan water content
Pyranometer / PAR sensorn Manufactured by ApogeeInstrumentsn Configured to connect toour Em50n Measures total solarradiation (W/m2), PARsensor measures µmol/m2/sn Important for energybalance studies andmicro-climate monitoring.n Comes with leveling plate
Cup Anemometer• For use with Em50 only, measures bothspeed and direction
Em50R Radio-enabled Loggern Any number of Em50Rs cantransmit to one Data Stationor Rm1.n Range is from 1 to 3 km,depending on interference.Range can be increasedwith use of antenna.n Transmits data whenmeasurement is takenSame specifications as normal Em50, only Em50R has aradio transmitter that sends collected data via telemetry
DataStation• Collects data from anynumber of Em50Rs• Can operate on solar poweror AC power• Download direct to PC orPDA at your convenience• Has Radio Telemetry testcapability to help withplacing Em50R loggers.
Em50G: What is it?GSM-enabled logger,delivers data via GSMproviders to Decagon’sserverData is available at anyinternet connection
Why the Em50G?• 2.4 Ghz Radio can be problematic (range,wifi interference)• Single point remote locations• Ease of data acquisition via internet
Computer + Software+ Internet Em50GLogger + SensorsGSM/GPRSCell TowerInternetDecagonInternet Server64How does it work?
ECHO UtilityYou can:n Configure portsn Name loggern Set logging intervaln Download datan Scan ports- Does not graph- Cannot applycalibrations inprogramFree software thatcomes with anyEm50 and Em5bpurchase
CTD (conductivity, temp., depth sensor)Decagon Devices, Inc.Confidential and ProprietaryDo Not Copy or Redistribute66Water DepthRange 0 to 3.5 mAccuracy ±0.2 % of spanResolution 1 mmElectrical ConductivityRange 0 to 120 dS/m (mS/cm)Accuracy ±5% of readingResolution 1.2% of readingTemperatureRange -40 to + 50 °CAccuracy ±1 °CResolution 0.1 °C
CTD Usesn StreambedsDecagon Devices, Inc.Confidential and ProprietaryDo Not Copy or Redistribute67• Piezometer wells
ES-2 EC and T sensorn For monitoring EC andtemperature in liquid waterRange:Electrical Conductivity: 0 to 120 dS/mTemperature: -40 to 50°CResolution:Electrical Conductivity: 0.001 dS/mTemperature: 0.1°CAccuracy:Electrical Conductivity: + 0.01 dS/m or + 10 %(whichever is greater)Temperature: + 1°C
Drain Gauge G-2: How it works1. Drain Gauge is installed below theroot zone2. Water travels through divergencecontrol tube, then through wick tomeasurement chamber.3. Water level is continuouslymonitored by depth sensor insidechamber. When 31ml of water fillsthe chamber, it empties via asiphon into a collection chamber.Each siphon event corresponds to1mm of infiltration.4. Water samples can be extractedfrom collection chamber using asyringe.5. Excess water exits through theoverflow port, leaving a constantvolume in the sampling reservoir.
Drain Gauge G3n Sampling Reservoir Volume: 3 Ln Accuracy: ± 2% of full scalen Total Length: 1.5mn Divergence Control Tube (DCT) Length :60 cmn Construction Material: Stainless Steel or PVCDCTDecagon Devices, Inc.Confidential and ProprietaryDo Not Copy or Redistribute73• Measure deep drainage flux(past the root zone)• Analyze water samples• Also measures EC and Temp.• Sealed lower portion
Decagon Devices, Inc.Confidential and ProprietaryDo Not Copy or Redistribute74
Thermal Conductivity,Thermal Diffusivity,Thermal Resistivity andSpecific Heat Capacity.n Extendedtemperature range:-50 to 150°C.n Data storage.n Smart sensorsn Can be used withliquid samples.PRO
KD2 Pro Applications:n Soil thermalproperties (fire, sun)