PP Systems TARGAS-1, Operation Manuals

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TARGAS-1 Operation Manual V. 1.02 154 support@ppsystems.com
Definition of Symbols and Physical Constants Used in Equations
Measured Parameters
Symbol Parameter Unit
𝑽𝑽
𝟎𝟎
Flow rate of dry air into cuvette at STP cc min -1
𝒂𝒂
Projected leaf area cm
2
𝑯𝑯
𝒃𝒃
Boundary layer resistance to water vapor m
2
s mol
-1
𝑷𝑷
Atmospheric pressure mb
𝑸𝑸
Photon flux density incident on cuvette µmol m
-2
s
-1
𝑻𝑻
𝒄𝒄
Cuvette air temperature °C
Calculated Parameters
Symbol Parameter Unit
𝑾𝑾
Mass flow of air per unit leaf area into cuvette mol m
-2
s
-1
𝒆𝒆
𝒊𝒊𝒊𝒊
Partial pressure of water vapor of air entering cuvette = H
2
Or mb *
𝒆𝒆
𝒎𝒎𝒐𝒐𝒐𝒐
Partial pressure of water vapor of stirred cuvette air = H
2
Oa mb *
𝑬𝑬
Transpiration rate mmol m
-2
s
-1
𝒆𝒆
𝒎𝒎𝒆𝒆𝒂𝒂𝒍𝒍
Saturated vapor pressure (inside the leaf) at leaf temperature mb
𝑻𝑻
𝒎𝒎𝒆𝒆𝒂𝒂𝒍𝒍
Leaf temperature °C
∆𝒐𝒐
Temperature difference between the air and the leaf °C
𝑯𝑯
Radiation absorbed by the leaf W m
-2
𝑯𝑯
𝒔𝒔
Stomatal resistance to water vapor m
2
s mol
-1
𝒈𝒈
𝒔𝒔
Stomatal conductance to water vapor mmol m -2 s -1
𝑪𝑪
𝒊𝒊𝒊𝒊
CO
2
concentration of air entering cuvette = CO
2
r µmol mol
-1
*
𝑪𝑪
𝒎𝒎𝒐𝒐𝒐𝒐
CO
2
concentration of air inside and exiting the cuvette = CO
2
a µmol mol
-1
*
𝑨𝑨
CO
2
Assimilation rate (net photosynthesis) µmol m
-2
s
-1
𝒈𝒈
𝒄𝒄
Total conductance to CO
2
transfer mmol m
-2
s
-1
𝒈𝒈
𝒐𝒐𝒎𝒎𝒐𝒐𝒂𝒂𝒎𝒎
Total conductance to H
2
O transfer mmol m -2 s -1
𝑪𝑪
𝒊𝒊
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
𝝀𝝀
Latent heat of vaporization of water 45064.3 - (T
c
x 42.9) J mol
-1
𝑴𝑴
𝒂𝒂
Molecular mass of air 28.97
𝑪𝑪
𝒑𝒑
Specific heat at constant pressure 1.012 kJ kg -1 K -1
𝟒𝟒
Stefan Boltzmann constant 5.6704 x 10
-8
W m
-2
K
-4