PP Systems TARGAS-1, Operation Manuals

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TARGAS-1 Operation Manual V. 1.02 78 support@ppsystems.com
Definition of Symbols and Physical Constants Used in Equations
Measured Parameters
Symbol Parameter Unit
V
0
Flow rate of dry air into cuvette at STP cc min -1
a
Projected leaf area cm
2
r
b
Boundary layer resistance to water vapor m
2
s mol
-1
P
Atmospheric pressure mb
Q
Photon flux density incident on cuvette µmol m
-2
s
-1
T
c
Cuvette air temperature °C
Calculated Parameters
Symbol Parameter Unit
W
Mass flow of air per unit leaf area into cuvette mol m
-2
s
-1
e
in
Partial pressure of water vapor of air entering cuvette = H
2
Or mb *
e
out
Partial pressure of water vapor of stirred cuvette air = H
2
Oa mb *
E
Transpiration rate mmol m
-2
s
-1
e
leaf
Saturated vapor pressure (inside the leaf) at leaf temperature mb
T
leaf
Leaf temperature °C
∆ t
Temperature difference between the air and the leaf °C
H
Radiation absorbed by the leaf W m
-2
r
s
Stomatal resistance to water vapor m
2
s mol
-1
g
s
Stomatal conductance to water vapor mmol m -2 s -1
C
in
CO
2
concentration of air entering cuvette = CO
2
r µmol mol
-1
*
C
out
CO
2
concentration of air inside and exiting the cuvette = CO
2
a µmol mol
-1
*
A
CO
2
Assimilation rate (net photosynthesis) µmol m
-2
s
-1
g
c
Total conductance to CO
2
transfer mmol m
-2
s
-1
g
total
Total conductance to H
2
O transfer mmol m -2 s -1
C
i
CO
2
concentration of sub-stomatal cavity µmol mol
-1
* Detected by IRGAs, temperature and pressure corrected, effects of foreign gas broadening (water vapor
effects) on measurement corrected.
Physical Constants
Symbol Parameter Value