| Term |
|
Units |
|
Definition |
| Agross |
|
|
|
Gross rate of CO2 uptake per unit
leaf area |
| Anet (A) |
|
m mol m-2
s-1 |
|
Net rate of CO2 uptake per unit
leaf area |
| Ac |
|
m mol m-2
s-1 |
|
Net canopy rate of CO2 uptake per
unit ground area |
| Ac,tot |
|
g m-2 yr-1 |
|
Ac integrated over the course of a
year |
| Ac,sun |
|
m mol m-2
s-1 |
|
Net rate of CO2 uptake per unit
area sunlit leaves |
| Ac,shade |
|
m mol m-2
s-1 |
|
Net rate of CO2 uptake per unit
area shaded leaves |
| Aseed |
|
m mol m-2
s-1 |
|
Carbon available for partitioning from planted
seeds |
| Astroot |
|
m mol m-2
s-1 |
|
Carbon available for partitioning from storage
roots |
| A¢ |
|
m mol m-2
s-1 |
|
Predicted rate of CO2 uptake |
| a |
|
day-1 |
|
Respiration coefficient |
| b |
|
day-1 |
|
Respiration coefficient |
| ca |
|
m mol mol-1 |
|
Atmospheric CO2 concentration |
| cf |
|
|
|
Curvature factor |
| ci |
|
m mol mol-1 |
|
Intercellular concentration of CO2
in air corrected for solubility relative to 25oC |
| cp |
|
J Kg-1 K-1 |
|
Specific heat capacity of dry air |
| Cov |
|
|
|
Coefficient of variation |
| Cp |
|
mol m-2 |
|
Leaf inorganic phosphate pool concentration |
| Cx |
|
mol m-2 |
|
Leaf sugar phosphate pool concentration |
| Ct |
|
mol m-2 |
|
Leaf starch phosphate pool concentration |
| Cc |
|
mol m-2 |
|
Leaf cytosolic sucrose pool concentration |
| Cv |
|
mol m-2 |
|
Leaf vacuolar sucrose pool concentration |
| Ca |
|
mol m-2 |
|
Leaf apoplastic sucrose pool concentration |
| Cl |
|
mol m-2 |
|
Stem loading volume |
| Cu |
|
mol m-2 |
|
Stem unloading volume |
| Cr |
|
mol m-2 |
|
Sink labile sucrose pool concentration |
| Cw |
|
mol m-2 |
|
Total dry weight growth in sink |
| Ch |
|
mol m-2 |
|
Sink vacuolar sucrose |
| Dj |
|
d |
|
Julian day (day of year) |
| Dstart |
|
d |
|
Day of year on which the sinusoidal
temperature function is assumed to start |
| d |
|
dimensionless |
|
Zero plane displacement |
| E |
|
(J mol-1) |
|
Activation energy: |
| El |
|
mmol m-2 s-1 |
|
Evapo/transpiration rate at sunlit/shaded
leaves in a canopy layer |
| Ec |
|
mmol m-2 s-1 |
|
Instantaneous canopy evapo/transpiration rate |
| Ed |
|
mol m-2 day-1 |
|
Cumulative daily evaporation from the soil
surface. |
| Esoil |
|
mol m-2 s-1 |
|
Evaporation from the soil surface |
| Etot |
|
mmol m-2 yr-1 |
|
Ec integrated
over the course of a year |
| eL |
|
kPa |
|
Saturated water VPD in the leaf |
| Fcanopy |
|
(m2 m-2) |
|
Canopy leaf area index |
| Fshade |
|
(m2 m-2) |
|
Canopy shaded leaf area index |
| Fsun |
|
(m2 m-2) |
|
Canopy sunlit leaf area index |
| Fsum |
|
(m2 m-2) |
|
Summed leaf area index from top of canopy to
layer considered in calculation |
| ga |
|
(mmol m-2 s-1) |
|
Leaf boundary layer conductance |
| gs |
|
(mmol m-2 s-1) |
|
Leaf stomatal conductance |
| gs¢ |
|
(mmol m-2 s-1) |
|
Predicted leaf stomatal conductance |
| gc |
|
(mmol m-2 s-1) |
|
Canopy conductance of CO2 |
| gwmod |
|
|
|
Water stress stomatal conductance modifier |
| gws |
|
|
|
Species dependent water stress sensitivity
factor |
| g0 |
|
dimensionless |
|
Stomatal slope factor |
| g1 |
|
dimensionless |
|
Stomatal intercept factor |
| h |
|
|
|
Simulated total daily rainfall |
| hr |
|
h |
|
Hour of day |
| hs |
|
% |
|
Relative humidity |
| hcanopy |
|
m |
|
Height of canopy |
| hms |
|
m |
|
Wind speed measurement height |
| hlayer |
|
m |
|
Height of canopy layer above ground |
| I |
|
m mol m-2
s-1 |
|
Photon flux |
| Iabs |
|
m mol m-2
s-1 |
|
Photon flux absorbed by either sunlit or
shaded leaves within a canopy layer |
| Idir |
|
m mol m-2
s-1 |
|
Photon flux in direct solar beam |
| Idiff |
|
m mol m-2
s-1 |
|
Photon flux in diffuse radiation |
| Itotal |
|
m mol m-2
s-1 |
|
Total photon flux incident on canopy |
| Is |
|
m mol m-2
s-1 |
|
Solar constant, photon flux in a plane
perpendicular to the solar beam above the atmosphere |
| Isoil |
|
m mol m-2
s-1 |
|
Photon flux incident on the soil surface |
| Ja |
|
J s-1 |
|
Total solar radiation incident on sunlit or
shaded leaves within a canopy layer |
| Jox |
|
mol m-2 s-1 |
|
Photosynthetic assimilation rate (Aleaf) |
| Jxt |
|
mol m-2 s-1 |
|
Rate of sugar phosphate conversion to starch |
| Jtx |
|
mol m-2 s-1 |
|
Rate of re-conversion of starch to sugar
phosphate |
| Jxc |
|
mol m-2 s-1 |
|
Rate of conversion from sugar phosphate to
cytosolic |
| Jal |
|
mol m-2 s-1 |
|
Rate of transfer from apoplastic to loading at
phloem |
| Jla |
|
mol m-2 s-1 |
|
Reverse transfer from loading phloem to
apoplastic |
| Jcv |
|
mol m-2 s-1 |
|
Rate of transfer from cytosolic to vacuolar
pools |
| Jvc |
|
mol m-2 s-1 |
|
Reverse transfer rate from vacuolar to
cytosolic pools |
| Jac |
|
mol m-2 s-1 |
|
Reverse transfer from apoplastic to cytosolic
pool |
| Jca |
|
mol m-2 s-1 |
|
Rate of transfer between cytosolic and
apoplastic pool |
| Jlu |
|
mol m-2 s-1 |
|
Sucrose transfer rate in phloem |
| Jur |
|
mol m-2 s-1 |
|
Rate of unloading from phloem to labile
sucrose pool |
| Jrh |
|
mol m-2 s-1 |
|
Rate of transfer between labile and sink
vacuolar pool |
| Jhr |
|
mol m-2 s-1 |
|
Rate of transfer between labile and sink
vacuolar pool |
| Jro |
|
mol m-2 s-1 |
|
Rate of sink associated respiration |
| Jwr |
|
mol m-2 s-1 |
|
Rate of growth matter flow to sink labile
sucrose pool |
| Jrw |
|
mol m-2 s-1 |
|
Rate of growth formation from labile sucrose
pool |
| k |
|
dimensionless |
|
Foliar absorption coefficient |
| KCO2 |
|
mol m-2 s-1 |
|
Initial slope of photosynthetic CO2
response |
| KN |
|
dimensionless |
|
Canopy nitrogen extinction coefficient |
| kleaf |
|
dimensionless |
|
Carbon partitioning coefficient to the leaf |
| kstem |
|
dimensionless |
|
Carbon partitioning coefficient to the stem |
| ksroot |
|
dimensionless |
|
Carbon partitioning coefficient to the
structural root |
| kstroot |
|
dimensionless |
|
Carbon partitioning coefficient to the storage
root |
| kfroot |
|
dimensionless |
|
Carbon partitioning coefficient to the fine
root |
| kseed |
|
dimensionless |
|
Carbon partitioning coefficient to the seed |
| kslope |
|
mol m-1 |
|
Initial slope of photosynthetic light response |
| kwind |
|
dimensionless |
|
Wind extinction coefficient |
| kxx |
|
s-1 |
|
Michaelis-Menten rate constants associated
with the mechanistic carbon partitioning model. |
| L (i) |
|
m m-3 |
|
Rooting density in soil layer i |
| Lb |
|
|
|
Leaf boundary layer conductance |
| LCP |
|
|
|
Light compensation point |
| LN |
|
g m-2 |
|
Leaf nitrogen concentration |
| Lw |
|
m |
|
Leaf width in the direction of the wind |
| l |
|
m2 m-2 |
|
Leaf area index of sunlit or shaded leaves
within a canopy layer, (l= lsun or l= lshade) |
| lsun |
|
m2 m-2 |
|
Leaf area index of sunlit leaves within a
canopy layer |
| lshade |
|
m2 m-2 |
|
Leaf area index of shaded leaves within a
canopy layer |
| n |
|
days |
|
Number of days in a month |
| Neff |
|
|
|
Effective length of rainy days |
| nr |
|
days |
|
Number of rainy days in a month |
| nsoil |
|
|
|
Number of soil layers |
| p |
|
|
|
Probability that there will be no rainfall |
| P |
|
kPa |
|
Atmospheric pressure |
| Pday |
|
day |
|
Planting day (applies to annual plants) |
| Po |
|
kPa |
|
Standard atmospheric pressure at sea level |
| Ps |
|
kPa |
|
Leaf surface partial pressure of CO2
|
| PSII |
|
m mol m-2
s-1 |
|
Irradiance absorbed by photosystem II |
| r v¢
|
|
|
|
Saturated water vapour concentration (look up
table) |
| r |
|
Kg m-3 |
|
Density of dry air (look up table) |
| q |
|
dimensionless |
|
Probability of rainfall on a given day |
| Q10 |
|
dimensionless |
|
Is the proportional rise in a parameter for a
10oC increase in temperature |
| r |
|
dimensionless |
|
Leaf reflection coefficient for total solar
radiation |
| r~ |
|
|
|
Mean daily rainfall |
| R |
|
J k-1 mol-1 |
|
Real gas constant |
| Ro |
|
m mol m-2
s-1 |
|
Dark respiration rate at 25oC |
| Rd |
|
m mol m-2
s-1 |
|
Dark respiration at a given temperature |
| Rs |
|
m3 kg-1 s-1 |
|
Soil resistance |
| RI |
|
m3 kg-1 s-1 |
|
Soil interface resistance |
| Rr |
|
m3 kg-1 s-1 |
|
Root endodermis resistance |
| Rx |
|
m3 kg-1 s-1 |
|
Stem xylem resistance |
| RL |
|
m3 kg-1 s-1 |
|
Leaf resistance |
| Rtotal |
|
m mol m-2
s-1 |
|
Total plant respiration (dark+photo) |
| s |
|
kPa K-1 |
|
Slope of saturated water vapour pressure
change with respect to temperature (look up table) |
| sc |
|
g m-2 |
|
Soil carbon content |
| sn |
|
g m-2 |
|
Soil nitrogen content |
| sp |
|
|
|
Spectral imbalance |
| Sr |
|
|
|
Soil reflectance |
| St |
|
|
|
Soil transmissivity |
| Ssize |
|
m |
|
Average size of soil particles |
| t |
|
h |
|
Time of day |
| TP |
|
m mol mol |
|
Triose phosphate concentration in the leaf |
| tpu |
|
m mol m-2
s-1 |
|
Rate of triose phosphate utilization |
| tsn |
|
h |
|
Time of solar noon |
| tlen |
|
h |
|
Daylength |
| Tair |
|
oC |
|
Ambient air temperature |
| Tleaf |
|
oC |
|
Leaf temperature |
| Tsoil |
|
oC |
|
Soil temperature |
| T1 |
|
oC |
|
Annual mean air temperature |
| T2 |
|
oC |
|
Annual range in air temperature |
| T3 |
|
oC |
|
Average daily range in air temperature |
| T4 |
|
oC |
|
Maximum daily range in air temperature |
| u |
|
m s-1 |
|
Measured wind speed (at known height of 2m) |
| ulayer |
|
m s-1 |
|
Wind speed in a given canopy layer |
| usoil |
|
m s-1 |
|
Wind speed at soil surface |
| Vcmax |
|
m mol m-2
s-1 |
|
Maximum rubP saturated rate of carboxylation
at a given temperature |
| Vcmaxo |
|
m mol m-2
s-1 |
|
Maximum rubP saturated rate of carboxylation
at 25oC |
| VPD |
|
kPa |
|
Air, water vapour pressure deficit |
| Z max |
|
m |
|
Maximum depth of plant root penetration |
| Zsoil (i) |
|
m |
|
Vertical distance from soil surface to soil
layer i |
| zo |
|
m |
|
Roughness length |
| k |
|
dimensionless |
|
von Karman’s constant |
| c |
|
dimensionless |
|
The ratio of horizontal:vertical projected
area of leaves in the canopy segment |
| a |
|
dimensionless |
|
Atmospheric transmittance |
| a slope |
|
mol m-1 |
|
Initial slope of photosynthetic CO2
response |
| b |
|
dimensionless |
|
Curvature parameter |
| d |
|
o |
|
Solar declination |
| W |
|
o |
|
Latitude |
| q |
|
o |
|
Solar zenith angle |
| q curve |
|
dimensionless |
|
Curvature parameter |
| qsoil,N |
|
m3 m-3 |
|
Water volumetric content of the soil layer N |
| q* |
|
m3 m-3 |
|
Field capacity of the soil |
| q1 |
|
m3 m-3 |
|
Critical value of the soil |
| q2 |
|
m3 m-3 |
|
Wilting point of the soil |
| t |
|
dimensionless |
|
Leaf transmission coefficient for solar
radiation |
| l |
|
MJ/Kg |
|
Latent heat of vaporization (look up table) |
| g |
|
Pa K-1 |
|
‘psychrometer constant’ (look up
table) |
| w |
|
g m-2 |
|
Total dry weight of all plant material |
| w leaf |
|
g m-2 |
|
Dry weight of material in leaf pool |
| w stem |
|
g m-2 |
|
Dry weight of material in stem pool |
| w sroot |
|
g m-2 |
|
Dry weight of material in the structural root
pool |
| w stroot |
|
g m-2 |
|
Dry weight of material in the storage root
pool |
| w froot |
|
g m-2 |
|
Dry weight of material in the fine root pool |
| w seed |
|
g m-2 |
|
|
