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NRES 408/808 Instrumentation Demonstration -- Radiation Instrumentation

NRES 408/808 Instrumentation Demonstration -- Radiation Instrumentation. Mark Mesarch 229D Hardin Hall 472-5904 or mmesarch1@unl.edu. Office Hours. Homework Assignment 4 on Blackboard Questions: Phone: 402.472.5904 e-mail: mmesarch1@unl.edu 229D Hardin Hall. Purpose of Demonstration.

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NRES 408/808 Instrumentation Demonstration -- Radiation Instrumentation

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  1. NRES 408/808Instrumentation Demonstration -- RadiationInstrumentation Mark Mesarch 229D Hardin Hall 472-5904 or mmesarch1@unl.edu

  2. Office Hours • Homework Assignment 4 on Blackboard • Questions: • Phone: 402.472.5904 • e-mail: mmesarch1@unl.edu • 229D Hardin Hall

  3. Purpose of Demonstration • Introduction to Instrumentation • NRES 469/869 Bio-Atmospheric Instrumentation • Examples ---- Not Exhaustive • More Than Just Numbers

  4. Net Radiation Budget Rn = RSW - RSW + RLW- RLW Where • Rn = Net Radiation • RSW = Short wave Incoming • RSW = Short wave Outgoing • RLW = Long wave Incoming • RLW = Long wave Outgoing

  5. Net Radiation Budget

  6. Net Radiation Budget Measured

  7. Net Radiation Budget Rn = RSW - RSW + RLW- RLW Where • Rn = Net Radiation • RSW = Short wave Incoming • RSW = Short wave Outgoing • RLW = Long wave Incoming • RLW= Long wave Outgoing

  8. Net Radiation Budget Rn = RSW - RSW + RLW- RLW At 13:30 on September 14 • RSW = 803.38 W m-2 • RSW = 141.16 W m-2 • RLW = 318.94 W m-2 • RLW= 523.05 W m-2 Rn = 803.38 – 141.16 + 318.94 – 523.05 = 458.11 W m-2

  9. Net Radiation Balance • Rn (Calculated) = 458.11 W m-2 • Rn (Measured) = 423.85 W m-2 • What Caused the Difference?

  10. Design Your Own Instrument Setup • What will the instrument “see”? • How is the instrument installed? • How to maintain the instrument?

  11. How Instruments “See” • Field of View (FOV) • Demo

  12. How Instruments See

  13. How Instruments See HemisphericalView

  14. How Instruments See

  15. How Instruments See Specific Field of View

  16. How Instruments See Hemispherical 24o Field of View

  17. How Instruments See Hemispherical 30oFOV Reifsnyder,W. 1967. Agr Meteorol 4: 255-265

  18. How Instruments See • Hemispherical vs specific Field of View (FOV) • Spatial coverage • Demo

  19. How Instruments See

  20. How Instruments See Spatial Measurement Alternative

  21. How Instruments See • Calculating absorbed fraction of radiant flux • Incoming (PARin) • Reflected (PARR ) • Transmitted (ART ) • Soil Reflected (PARSR) fAPAR= (PARin– PARR– PART+ PARSR) / PARin

  22. How Instruments See • Appropriate wavelength coverage

  23. How Instruments See • Individual measurements of incoming and outgoing long and shortwave radiation KZ CN4 net radiometer KZ CNR1 net radiometer

  24. How Instruments See • Incoming and outgoing all wave components KZ CNR2 net radiometer (Discontinued)

  25. How Instruments See • Single measurement of net radiation REBS Q*7.1 net radiometer KZ NR-Lite net radiometer

  26. How Instruments See • Hemispherical vs Field of View (FOV) • Spatial coverage • Appropriate wavelength coverage • Clear View : • Obstructions • Shadows • Mounting Frame • Single Plant vs Canopy

  27. How is Instrument Installed? • Mounting Frame

  28. How is Instrument Installed? • Mounting Frame • Direction

  29. How is Instrument Installed? • Direction : North vs South

  30. How is Instrument Installed? • Direction : Nadir vs Off-Nadir

  31. How is Instrument Installed? • Mounting Frame • Direction : • North vs South • Nadir (straight down) vs Off-nadir (45° ) • Height Above Canopy ????

  32. How is Instrument Installed? • Height Above Canopy: • Static height

  33. How Big is the Spot? 10 m

  34. How is Instrument Installed? • Mounting Frame • Direction : • North vs South • Nadir (straight down) vs Off-nadir (45° ) • Height Above Canopy: • Constant height above canopy • Static height • Row Crop vs Homogenous Canopy • Power Requirement

  35. Maintenance Requirements • Cleaning of Instruments

  36. Maintenance Requirements • Cleaning of Instruments • Bird damage and droppings • Rodent damage to wires

  37. Maintenance & Repair Rodent Damage

  38. Maintenance Requirements • Desiccant Checks

  39. Maintenance Requirements • Cleaning of Instruments • Desiccant Checks • Leveling

  40. Maintenance Requirements • Level • 2o off Level

  41. Calibration • Factory and “in house” Calibrations • Frequency • Wavelength Characterization

  42. Calibration • Factory and “in-house” Calibration References Eppley PSP pyranometers and Li-CorPyranometers

  43. What Is A “Measurement”? • Output – millivolt and volts • Simple conversion to radiant flux by multiplying output times calibration coefficient • Response time • Frequency of measurement - ????? • Instantaneous vs Average

  44. Calibration • Factory and “in-house” Calibration References

  45. Net Radiation Balance Rn (Calculated) = 458.11 W m-2 | Rn (Measured) = 423.85 W m-2 • What Caused the Difference? • Location of Instruments • Wavebands of Instruments • Calibration of Instruments • Level/Cleanliness • Rounding Errors

  46. Questions? • What Instruments See • How to Install Instruments • How to Maintain the Instruments

  47. Mark Mesarch • 229D Hardin Hall • 402.472.5904 or mmesarch1@unl.edu • Assignment 4 on Blackboard (DUE: Sept 30)

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