Geoscience Reference
In-Depth Information
Shelter factors
: mutual sheltering of leaves in a canopy raises the effective
value of boundary-layer resistances by empirical shelter factors of the order
of 2 to 3.
●
Stomatal resistance
: in dry canopies water mainly evaporates inside the
leaves so, in addition to boundary-layer resistance, latent heat (and CO
2
) flux
also has to pass through a stomatal resistance associated molecular diffusion
through the plants' stomata.
●
Single leaf Penman-Monteith equation
: simultaneously solving the energy
balance equation for a single leaf and equations that control the rate of diffu-
sion of heat fluxes through boundary-layer resistances and stomatal resistance
gives the Penman-Monteith equation for a single leaf, see Equation (21.29).
●
Whole-canopy Penman-Monteith equation
: the single source or 'big leaf '
representation of energy balance for a canopy (with
surface resistance
taken
as the canopy average of all stomatal resistances acting in parallel, and
aerodynamic resistance
as the sum of turbulent transfer resistance and canopy
average boundary-layer resistance acting in series) gives the whole-canopy
Penman-Monteith Equation using a derivation analogous to that for a single
leaf, see Equation (21.33).
●
References
Monteith, J.L. (1965) Evaporation and environment.
Symposium of the Society for
Experimental Biology
, 205-234; republished in Gash, J.H.C. and Shuttleworth, W.J.,
(2007)
Benchmark Papers in Hydrology: Evaporation
. IAHS Press, Wallingford, 521p.
Monteith, J.L. and Unsworth, M.H. (1990)
Principles of Environmental Physics
. Edward
Arnold, London, p. 291.
Thom, A.S. (1968) The exchange of momentum, mass, and heat between an artificial leaf
and the airflow in a wind-tunnel.
Quarterly Journal of the Royal Meteorological Society
,
94
19
, 44-55.
Waggoner, P.E. and Reifsnyder, W.E. (1968) Simulation of the temperature, humidity, and
evaporation profiles in a leaf canopy.
Journal of Applied Meteorology
,
, 400-409.
Waggoner, P.E. and Reifsnyder, W.E. (1969) Simulation of the microclimate in a forest.
Forest Science
,
7
, 37-40.
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