LI-COR LI-870, Инструкция по использованию

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Appendix B. Equations summary
B-14
where f
c
( x ) is a function whose inverse is a double rectangular hyperbola, and
whose coefficients (
a1
…
a4
) are given on the calibration sheet.
B-15
Solving equation B-15 for
C
yields the calibration function
B-16
Where
B-17
ψ
(
W
) accounts for band broadening by water vapor.
B-18
The band broadening coefficient
h
(
α
'
c
) has been determined to be 1.45 for the
instrument for CO
2
concentrations near ambient. At higher concentrations, the
value decreases. We capture this behavior with an empirical relationship (equation
B-19).
B-19
Where
z
is from equation B-12, 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
typical relationship between
h
(
α
'
c
) and CO
2
concentration is shown in Figure B-1
on the facing page. (‘Typical’ because the exact relationship depends on the rela-
tionship between absorptance and CO
2
, which is the calibration curve.)
B-4 Using the LI-870 CO₂/H₂O Analyzer