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Recent results towards verification of measurement uncertainty for CLARREO IR measurements

Recent results towards verification of measurement uncertainty for CLARREO IR measurements. John Dykema CLARREO SDT, 2012 Hampton, VA. On-orbit Test/Validation (OT/V) Modules. (Measures instrument line shape). Heated Halo. (used in combination with space view for instrument calibration).

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Recent results towards verification of measurement uncertainty for CLARREO IR measurements

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  1. Recent results towards verification of measurement uncertainty for CLARREO IR measurements John Dykema CLARREO SDT, 2012 Hampton, VA

  2. On-orbit Test/Validation (OT/V) Modules (Measures instrument line shape) Heated Halo (used in combination with space view for instrument calibration) (Includes Multiple Phase Change Cells for absolute temperature calibration and Heated Halo for spectral reflectance measurement ) QCL Laser (used for blackbody reflectivity and Spectral Response Module) • Viewing configuration providing immunity to polarization effects. Wisconsin & Harvard Technology Developments Under NASA IIP

  3. DARI Testbed (1)

  4. QCL Housing: Optics, Thermal Management, Electronics New kinematic lens mount

  5. Quantum Cascade Laser Housing – Exploded View Purge valve Relief valve (for use during purge) House-keeping sensor unit (T,p,RH) Emission window (AR coated ZnSe) QCL device mounting clamp Collimating optic/mount Thermal cold plate TEC and electrical connection Mounting structure

  6. QCL Electronics and Built-In Housekeeping

  7. Collimation of 60°-40° output QCL device QCL Asphere Collimated Beam

  8. QCL Electronics Chassis

  9. Vacuum and Thermal Management

  10. OSRM: TRL 5 Flip mirror Blackbodies for thermal testing Laser power meter QCL w/ integrated housekeeping Chilled ethanol QCL thermal management Electronics bus

  11. Vacuum Test Results

  12. Vacuum Test Results (2) Results of vacuum test runs Thermal requirements for different QCL packaging options

  13. DARI Testbed (2)

  14. OSRM: TRL 6 System level test with CO2 laser, integrating sphere: an absolute IR lineshape standard

  15. OSRM : CO2 to QCL ILS Comparison (1) QCL, when T and I specifications are met, matches CO2 laser lineshape MCT Detector

  16. OSRM : CO2 to QCL ILS Comparison (2) Pyroelectric Detector

  17. DARI Testbed ILS

  18. OCEM-QCL TRL 6 Inferring emissivity from laser reflection

  19. Calibrated, Illuminated Blackbodies Pyroelectric Detector MCT Detector

  20. Calculation of Power on Detector

  21. Optical Modeling for OCEM-QCL f: div angle Reflected Laser Light to FTS and Detector d q

  22. Compute Cavity Emissivity Cf=39 (Knuteson et al. J.TECH 2004)

  23. QCL Subsystem: Pathway to TRL 7

  24. Current Sensing Power Conditioning Filter + + Output Power In Switching RegulatorController - - FB β Setpoint Temperature Offset TEC Controller

  25. TEC Controller • Single Supply Operation • High Efficiency • No Heat Sink Necessary • Buffered Temperature Readout • Remote/Local Setpoint

  26. V/I Board Modified Howland Current Source + Input Waveform LASER Protection - Voltage Monitoring V Power Monitoring Current Monitoring I Temperature Monitoring T IOUT + VIN - To LASER

  27. V/I Board • Single Supply Operation • No Heat Sink Required • (depending on LASER current) • Multiple Monitoring Options: • LASER Voltage, Current (Power) • LASER Temperature • ESD Protection

  28. In Situ Temperature

  29. Temporal Drift in Measurement = Satellite overpass

  30. Spatial Drift in Measurement

  31. First Assessment of Uncertainty Practices From Immler et al., AMT 2010

  32. Atmospheric Satellite Measurement Satellites make wavelength-dependent measurements of radianceR: retrieve x (temperature, humidity, clouds, trace gases, surface properies)

  33. Infrared Profiling Process

  34. Site Atmospheric State Best Estimate Radiosondes drift in time and space Radiosondes ascent time much greater than satellite measurement length Solution: use ancillary measurements to interpolate in space and time One approach: Tobin et al., “Atmospheric Radiation Measurement site atmospheric state best estimates for Atmospheric Infrared Sounder temperature and water vapor retrieval validation,” JGR 2006 See also Calbet et al., AMT, 2011

  35. Tobin 2006 Approach to SASBE Two sondes were launched within 2 hours of overpass time Interpolate sonde profiles in time with IR-based atmospheric profiling Interpolate sonde profiles in space with geostationary measurements Perform weighted average of interpolated profiles to get best estimate of atmospheric column

  36. Blackbody Calibration and Uncertainty • Practical Blackbody: • Finite Aperture •Temperature Gradients

  37. Uncertainty Assessment for Vector Quantities Uncertainty Assessment: In Situ Temperature Profile TSASBE Uncertainty Assessment: Infrared Temperature Profile x

  38. Acknowledgements Thanks to NASA for: IIP funding (ESTO) IPT funding (LaRC) SDT funding

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