The band broadening coefficient h(α
c
) has been determined to be 1.45 for the LI-840A for CO
2
concentrations near ambient. At higher concentrations, the value decreases. We capture this
behavior with an empirical relationship (equation B-17).
B-17
Where z is from equation B-10, and b
w
is the low concentration band broadening coefficient:
1.45. This is the value shown on the calibration sheet as BB=1.45. The present value of h(α
c
) is
viewable on the Diagnostics screen (Section 3). The typical relationship between h(α
c
) and CO
2
concentration is illustrated below. (‘Typical’ because the exact relationship depends on the rela-
tionship between absorptance and CO
2
, which is the calibration curve.)
Appendix B
Appendix B. Equation SummaryB-6
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