Pyrgeometer Calibration via Regression

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Pyrgeometer Calibration via Regression

• Three PIRs with three thermistors were calibrated
  against the WISG at DAVOS
• Other PIRs were then calibrated outdoors against
  this triad over several weeks via a regression
  technique using the following equations

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Comparison of Triad Average vs Cox Albrecht
Regression Calibration of PIR
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Minute-by-Minute Comparisons
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Comparison of Triad Average vs Reda et al.
Regression Calibration of PIR
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Minute-by-Minute Comparisons
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Comparison of Triad Average vs Philipona
Regression Calibration of PIR
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Minute-by-Minute Comparisons
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Conclusions

• Assuming the WISG is an absolute reference
• - Cox and Albrecht produce 2? uncertainties of
  3-4 Wm-2 with noticeable diurnal
  differences
• - Reda et al. or Philipona produce 2?
  uncertainties of ? 1.25 Wm-2 with no large
  diurnal differences
• A problem (Forgan comment) is that the values of
  these regressed coefs differs significantly from
  the blackbodyoudoor calibration