PP Systems CIRAS-2 - Symbol Definitions; Measured Parameters; Calculated Parameters

Appendix 3. Photosynthesis Equations Used in CIRAS-2
CIRAS-2 Operator's Manual Version 2.04
- 159 -
(6.2) Where:
Please note: These calculations are based on the following assumptions:
i) the leaf is exposed on both upper and lower leaf surfaces
ii) the upper and lower boundary layer resistances are similar
iii) stomata are evenly distributed on both upper and lower leaf surfaces.
Symbol Definitions
Measured Parameters
Symbol
Measured Parameter
Unit
V
20
Mass flow of dry air into cuvette at STP
cm
3
sec
-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
Calculated Parameter
Unit
W
Mass flow of dry air per unit leaf area
mol m
-2
s
-1
e
in
Partial pressure of water vapor of air entering cuvette
mb
e
out
Partial pressure of water vapor of stirred cuvette air
mb
E
Transpiration Rate
mmol m
-2
s
-1
e
s
Saturated vapor pressure at cuvette air temperature
mb
e
leaf
Saturated vapor pressure at leaf temperature, inside the leaf
mb