LI-COR LI-870, Инструкция по использованию

Страница: 33 / 42

where
V
c
and
V
co
are the raw detector signals for sample and reference,
Z
c
is the
CO
2
zero parameter, and X
wc
is a cross sensitivity parameter for the effect of water
vapor on CO
2
. Its value is reported on the calibration sheet as
XS=
.
The empirical pressure correction function
g
c
() depends on CO
2
absorptance and
pressure:
When P = P
o
, g
c
() = 1.
When
P
<
P
o
B-11
where
a
= 1.10158,
b
= -6.1217E-3,
c
= -0.266278,
d
= 3.69895, and
z
is the asymp-
totic value of absorptance, obtained from the calibration coefficients (equation
B-15).
B-12
When P > P
o
B-13
where
X
,
A
, and
B
are computed as in equation B-11. CO
2
concentration
C
(µmol
mol
-1
) is computed from
Appendix B. Equations summary
B-3 Appendix B. Equations summary