Leaf Porometer Operator’s Manual
6. Leaf Porometer Theory
65
The equation therefore becomes
(24)
Where
q
is
(25)
Both the saturation vapor pressure and its slope have strong
temperature dependence, but their ratio is a weak linear
function of temperature, so the final form of the equation
for
q
gives a value which is fairly constant with temperature
(though the temperature correction is made in code). At
room temperature a value of
q
= 0.1 appears to work well.
1
1
2
1
1
1
1
)
1
)(
(
ˆ
d
d
h
q
T
e
D
g
r
a
s
vapor
s
∆
−
−
∆
−
∆
=
ρ
*
10
3
.
4
071
.
0
)
(
*
)
(
*
4
1
1
γ
γ
γ
atm
a
s
atm
atm
a
s
P
T
x
T
e
P
sP
T
e
s
q
−
−
=
=
=
